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REINFORCED    CONCRETE 

L^ 

IN 

FACTORY    CONSTRUCTION 


PUBLISHED  BY 

1  THE  ATLAS  PORTLAND  CEMENT  COMPANY 
30    BROAD    STREET 
NEW  YORK,  N.  Y. 


Copyright  by 
THB  ATLAS  PORTLAND  CEMENT  COMPANY. 

1907. 
All  rights  reserved. 


>l 


INTRODUCTION. 


Reinforced  concrete  has  provided  for  the  manufacturer 
an  entirely  new  building  material.  Indestructible,  econom- 
ical and  fireproof,  it  offers  under  most  conditions  fea- 
tures of  advantage  over  every  other  type  of  construction. 
The  development  has  naturally  been  greatest  in  the  larger 
centers  of  population,  but  it  is  extending  rapidly  to  the 
remoter  districts,  and,  indeed,  wherever  new  buildings  are 
contemplated. 

This  widespread  interest  demands  an  authoritative 
treatment,  and  The  Atlas  Portland  Cement  Company  has 
embraced  this  opportunity  to  present  to  the  manufacturer, 
and  also  to  the  architect  and  the  engineer  who  are  not 
concrete  specialists,  a  brief  treatise  on  reinforced  con- 
crete for  factory  construction,  with  a  view  of  giving  a 
comprehensive  idea  of  the  advantages  and  limitations  of 
the  material  as  adapted  to  the  factory,  and  a  demon- 
stration of  its  value  as  illustrated  in  a  variety  of  buildings 
in  different  localities. 

The  work  has  been  prepared  by  a  consulting  engineer, 
Mr.  Sanford  E.  Thompson,  who  is  well  qualified  to  treat 
the  subject  as  an  expert  authority.  The  Atlas  Portland 
Cement  Company,  occupying  as  it  does,  a  somewhat 
unique  position  among  cement  manufacturers,  with  its 
wide  reputation  for  a  thoroughly  uniform  and  satisfactory 


product,  and  its  immense  production — greater  in  19O7 
than  that  of  any  other  four  cement  manufacturers  in  the 
world  — commends  the  book  to  its  readers  with  the  hope 
that  it  may  prove  a  fitting  sequel  to  the  former  publications 
of  the  company— "Concrete  Construction  About  the  Home 
and  On  the  Farm"  and  "Concrete  Country  Residences." 

THE  ATLAS  PORTLAND  CEMENT  COMPANY. 
New  York,  November,  19O7. 


PREFACE. 


This  book  may  not  be  regarded  as  a  complete  treatise  on  concrete  fact- 
ory construction,  but  it  has  been  the  aim  to  present  details  of  this  type  of 
construction  and  a  careful  description  of  typical  examples  of  concrete 
buildings  selected  from  various  sections  of  the  country  and  erected  by 
representative  builders.  Suggestions  are  thus  offered  to  the  factory  owner 
who  contemplates  building  in  reinforced  concrete,  while  at  the  same  time 
the  practical  details  may  prove  of  value  to  architects!  engineers  and 
builders. 

The  first  chapter  presents  to  the  manufacturer  a  brief  review  of  the  qual- 
ities of  reinforced  concrete  in  comparison  with  other  materials  for  factory 
buildings,  and  this  is  followed  by  a  chapter  giving  in  considerable  detail 
the  general  principles  of  design  with  information  in  regard  to  methods  of 
construction.  Chapter  III  treats  of  the  selection  of  the  aggregates.  These 
general  chapters  are  followed  by  ten  chapters,  each  describing  in  full  some 
one  shop,  factory  or  warehouse  of  reinforced  concrete,  selected  with  a 
view  of  presenting  a  variety  of  the  more  usual  types  of  factory  and  ware- 
house construction. 

Chapter  XIV  outlines  with  illustrations  many  of  the  styles  and  systems 
of  reinforcement  in  common  use  in  building  construction,  and  briefly 
refers  to  examples  of  concrete  block  walls,  surface  finish,  concrete  pile 
foundations  and  tanks,  each  illustrated  by  photographs. 

All  illustrations,  excepting  a  part  of  those  in  Chapter  XIV,  have  been 
prepared  especially  for  this  book.  The  half-tones  are  made  from  original 
photographs,  and  the  designs  from  drawings  furnished  by  the  engineers 
and  contractors,  or  reproduced  in  the  office  of  the  author  from  the  original 
plans.  In  this  way  a  number  of  details  are  shown  which  seldom  appear  in 

3 


print.     Care  has  been  taken  throughout  to  give  complete  measurements  so 
that  the  figure*    may  be  used  as  a  guide  to  new  construction  work. 

The  Atlas  Portland  Cement  Company  presents  at  the  close  of  the  book 
letters  received  by  them  from  the  owners  of  the  plants  described  in  the 
various  chapters.  A  number  of  photographs  of  other  reinforced  concrete 
factories  are  also  reproduced. 

The  Atlas  Portland  Cement  Company,  and  the  undersigned,  desire  to 
express  their  appreciation  of  the  courtesies  extended  by  individuals  and 
companies  who  have  kindly  furnished  plans  and  data  for  incorporation 
Into  the  descriptive  chapters. 

SANFORD  E.  THOMPSON, 
November  1.  19O7.  Newton  Highlands,  Mass. 


CONTENTS. 


CHAPTER  I. 
FACTORY  CONSTRUCTION.  PAGE 

Cost    12 

Approximate  Cost  per  Cubic  Foot 12 

Safety  of  Reinforced  Concrete  Construction . 13 

Durability    13 

Fire  Resistance   14 

Insurance    15 

Stiffness 15 

Freedom  from  Vibration    16 

Versatility  of  Design    16 

Light    16 

Watertightness 16 

Cleanliness    16 

Rapidity  of  Construction    17 

Alterations    17 

Hanging    Shafting    17 

Bedding  Machinery    17 

Auxiliary  Equipment    17 

Foundations    18 

Power  Development   18 

Partitions    18 

Roof    18 

Tanks    18 

Letting  the  Contract   19 

Growth  of  Reinforced  Concrete  Construction 19 

APPENDIX:    Fire   Insurance   on   Reinforced   Concrete 21 

By  L.  H.  Kunhardt. 

CHAPTER  II. 

DESIGN  AND  CONSTRUCTION. 

Cement    24 

Brief  Specifications  for  Portland  Cement 25 

Specifications  for  Materials   25 

5 


Sand    * 

Screenings   25 

Gravel    25 

Broken  Stone  2S 

Water   26 

Reinforced  Steel   26 

Proportions  of  Materials  • 26 

Machine  Mixing 26 

Consistency    26 

Placing   27 

Surfaces    27 

Forms    27 

Foundations    28 

Basement   Floor    30 

Design  of  Floor  System  30 

Columns   35 

Walls    36 

Roofs 36 

Construction    36 


CHAPTER  III. 
CONCRETE  AGGREGATES. 

Effect  of  Different  Aggregates  upon  the  Strength  of  Mortar  and  Concrete 38 

General   Principles  for   Selecting  Stone 38 

Comparative  Values  of  Different  Stone 39 

General  Principles  for  Selecting  Sand 40 

Testing    Sand    

Calculating  Relative  Strengths  of  Mortars 43 

Testing  Concrete  Aggregates   ., 

Proportioning   Concrete    


CHAPTER  IV. 
PACIFIC  COAST  BORAX  REFINERY. 


...  47 

Proportions  of  the  Concrete 
Construction     ................... 

The  Fire   .. 

.........................................    55 

G 


CHAPTER  V. 
KETTERLINUS  BUILDING.  PAGE 

Design     6r 

Columns     64 

Column    Footings    •. 65 

Floor  System    66 

Stairs     67 

Walls     68 

Roof    68 

Construction     69 

Cost     73 

Insurance     73 

CHAPTER  VI. 
LYNN  STORAGE  WAREHOUSE. 

Floor    Construction    75 

Floor   Specifications    78 

Floor    Surface    80 

Test  of  Floor 80 

Columns     80 

Construction     82 

Forms     86 

Wall    Construction    87 

Partitions    87 

Waterproofing    87 

CHAPTER  VII. 
BULLOCK  ELECTRIC  MACHINE  SHOP. 

Design     89 

Columns 93 

Crane   Brackets    94 

Floor   System 94 

Walls 95 

Construction    Plant 96 

Gang     : ..,  ••  99 

Forms     , ,. 99 

1 


CHAPTER  VIII. 
WHOLESALE  MERCHANTS'  WAREHOUSE.  ™a 

103 

Layout    I04 

Beams  and  Slabs  ' .   vtj 

Columns    

waiis  •••  '.'.'.'.'.".'.  109 

Stairs    109 

Coal  Trestle   ^ 

Construction    

Cost    

CHAPTER  IX. 
BUSH  MODEL  FACTORY. 

. .  119 
Design    

Columns    

Floor  System   I23 

Walls    I2S 

Construction    I25 

CHAPTER  X. 
PACKARD  MOTOR  CAR  FACTORY. 

Floor   System    I31 

Columns    J36 

Stairs    l& 

Construction    J38 

Forms    '38 

CHAPTER  XL 
TEXTILE  MACHINE  WORKS. 

Columns    M7 

Floor   System    151 

Cost    156 

CHAPTER  XII. 
FORBES  COLD  STORAGE  WAREHOUSE. 

Details  of  Construction    160 

Girder   Frames 165 

Forms    167 

Construction    Plant    167 

Materials  and  Cos*    -.,,,-,, 167 

I 


CHAPTER  XIII. 

BLACKSMITH  AND  BOILER  SHOP  OF  THE  ATLAS  PORTLAND  CEMENT  Co.          PAGE 

Design     169 

Construction    169 

Coal    Trestle    176 

CHAPTER  XIV. 
DETAILS  OF  CONSTRUCTION. 

Systems   of   Reinforcement    178 

Factory   Molded  Concrete    190 

Concrete  Block  Walls   194 

Concrete  Metal  Walls   195 

Surface    Finish 195 

Concrete   Pile   Foundations    197 

Tanks     202 

MISCELLANEOUS  BUILDINGS. 
LETTERS. 


CHAPTER  I. 


FACTORY  CONSTRUCTION. 

A  manufacturer  about  to  build  a  factory  or  warehouse  must  choose  between 
several  types  of  construction.  In  this  selection  the  governing  considerations  are 
cost,  safety,  durability,  and  fire  protection,  while  many  minor  factors  enter  into 
each  individual  case. 

In  this  opening  chapter  the  qualities  of  the  different  materials  available  for 
factories  are  discussed  with  special  reference  to  the  reinforced  concrete. 

Types  of  buildings  for  mills,  factories,  and  warehouses  may  be  classified  as 
follows : 

(1)  Frame  construction; 

(2)  Steel   construction; 

(3)  Mill  or  slow  burning  construction; 

(4)  Reinforced  concrete  construction. 

The  first  and  cheapest  type  of  frame  construction  may  be  neglected  as  un- 
suitable for  permanent  installation  because  of  its  lack  of  durability  and  its  fire 
risk.  Board  walls,  narrow  floor  joists,  board  floors  and  roofs,  not  only  do  not 
protect  against  fire,  but  in  themselves  afford  fuel  even  when  the  contents  of  a 
factory  are  not  combustible. 

Steel  construction  with  concrete  or  tile  floors,  provided  the  steel  is  itself  pro- 
tected from  fire  by  concrete  or  tile,  is  efficient  and  durable,  but  its  first  cost  alone 
will  usually  prohibit  its  use  for  the  ordinary  factory  building. 

Mill,  or  "slow  burning,"  construction,  as  it  is  sometimes  called  to  distinguish 
it  from  fireproof  construction,  consists  of  brick,  stone,  or  concrete  walls,  with 
wooden  columns,  timber  floor  beams  and  thick  plank  floors,  which,  although  not 
fireproof,  are  all  so  heavy  as  to  retard  the  progress  of  a  fire  and  thus  afford  a 
measure  of  protection. 

Reinforced  concrete,  through  the  reduction  in  price  of  first-class  Portland 
cement  and  the  greater  perfection  of  the  principles  of  design,  has  lately  become  a 
formidable  competitor  to  both  steel  and  slow  burning  construction,  a  competitor 
of  steel,  not  only  for  factories  and  warehouses,  but  also  for  office  buildings,  hotels 
and  apartment  houses,  because  of  its  lower  cost,  shorter  time  of  construction,  and 
freedom  from  vibration ;  a  competitor  of  slow  burning  construction  because  of  its 
greater  fire  protection,  lower  insurance  rates,  durability,  freedom  from  repairs  and 
renewals,  and  even  in  many  cases,  its  lower  actual  cost. 

11 


COST. 

As  a  fundamental  principle  in  mill  and  factory  construction,  the  cost  must  be 
such  that  the  outlay  for  interest  on  construction,  running  expenses,  and  mainte- 
nance, shall  be  at  the  lowest  possible  minimum  consistent  with  conservative  design 
and  the  requirements  of  operation.  A  wooden  building  is  cheap  in  first  cost,  and 
therefore  in  interest  charges,  but  is  expensive  in  insurance  and  repairs,  while  the 
risk  of  the  loss  in  production  after  a  fire,  for  which  no  insurance  provides,  may 
far  counterbalance  any  theoretical  saving. 

As  a  general  proposition,  reinforced  concrete  is  almost  invariably  the  lowest 
priced  fireproof  material  suitable  for  factory  construction.  The  cost  is  nearly  always 
lower  than  that  for  brick  and  tile,  and  with  lumber  at  a  high  price,  it  is  fre- 
quently even  lower  than  brick  and  timber,  with  the  added  advantage  of  durability 
and  fire  protection. 

In  comparing  the  cost  of  different  building  materials,  one  must  bear  in  mind 
that  the  concrete  portion  of  the  building  is  only  a  part  of  the  total  cost.  Since  the 
cost  of  the  finish  and  trim  may  equal  or  exceed  that  of  the  bare  structure,  even  if 
the  concrete  itself  cost,  say,  10  per  cent,  more  than  brick  and  timber,  the  cost 
of  the  building  complete  may  not  be  5  per  cent,  greater  than  with  timber  interior. 
The  lower  insurance  rates  will  partly  offset  this  even  if  there  is  no  other  economical 
advantage  for  the  fireproof  structure. 

The  exact  cost  of  a  building  in  any  case  is  governed  by  local  conditions.  In 
reinforced  concrete,  the  design,  the  loading  for  which  it  must  be  adapted,  the 
price  of  cement,  the  cost  of  obtaining  suitable  sand  and  broken  stone  or  gravel, 
the  price  of  lumber  for  forms,  the  wages  of  the  laborers  and  carpenters,  are  all 
factors  entering  into  the  estimate.  Reinforced  concrete  is  largely  laid  by  common 
labor,  so  that  high  rates  for  skilled  laborers  affect  it  less  than  many  other  build- 
ing materials. 

APPROXIMATE  COST  PER  CUBIC  FOOT. 

As  a  general  proposition,  it  may  be  stated  that  the  cost  of  reinforced  concrete 
factories  finished  complete  with  heating,  lighting,  plumbing,  and  elevators,  but 
without  machinery  may  run,  under  actual  conditions,  from  8  cents  per  cubic  foot 
of  total  volume  measured  from  footings  to  roof,  to  12  cents  per  cubic  foot.  The 
former  price  may  apply  where  the  building  is  erected  simply  for  factory  purposes 
with  uniform  floor  loading,  symmetrical  design— permitting  the  forms  to  be  used 
over  and  over  again— and  with  materials  at  moderate  prices.  Several  of  the  build- 
ings of  simple  design  described  in  the  chapters  which  follow  come  in  this  class. 
The  higher  price  will  usually  cover  such  a  manufacturing  building  as  the  Ketter- 
linus,  described  in  Chapter  V,  located  in  a  restricted  district,  and  where  the  ap- 
pearance both  of  the  exterior  and  interior  must  be  pleasing.  This  does  not  include 
in  either  case  interior  plastering  or  partitions. 

12 


SAFETY  OF  REINFORCED  CONCRETE  CONSTRUCTION. 

In  any  type  of  building  there  is  more  or  less  danger  of  accident  during 
erection.  It  may  be  stated,  however,  that  with  ordinary  skill  in  design  and  con- 
struction there  is  no  more  liability  of  failure  with  reinforced  concrete  than  with 
other  structural  materials.  Accidents  which  have  occurred  can  be  traced  invariably 
to  a  disregard  of  elementary  principles  of  design  or  construction. 

Every  little  while  failures  of  steel  structures  occur  through  neglect  of  such  de- 
tails as  proper  riveting,  sufficient  bracing,  or  competent  design.  Even  brick 
buildings  are  by  no  means  immune  from  accidents  through  poor  workmanship 
or  ignorance.  For  example,  on  a  single  night  in  the  spring  of  1905,  the  walls  of 
several  apartment  houses  in  process  of  building  in  different  parts  of  New  York  city 
fell  down,  the  cause  being  undoubtedly  the  freezing  and  thawing  of  the  mortar. 
Yet  one  does  not  condemn  either  steel  or  brick  as  a  building  material.  Such 
failures,  whether  in  steel,  brick  or  concrete,  have  simply  emphasized  the  fact, 
and  it  cannot  be  too  strongly  insisted  upon,  that  a  thorough  knowledge  of  the 
theory  of  design  is  essential  as  well  as  experience  and  vigilant  inspection  during 
erection. 

For  reinforced  concrete  buildings  it  is  especially  important  that  the  designer 
be  competent,  and  that  the  builder  be  of  undoubted  experience  and  with  a 
knowledge  of  the  fundamental  principles  of  this  particular  type  of  construction. 
By  this  it  is  not  meant  that  the  builder  be  an  expert  mathematician,  but  he  should 
be  able  to  recognize  the  necessity  for  placing  the  steel  near  the  bottom  surface  of 
the  beams  and  slabs,  of  accurately  placing  all  the  steel  exactly  as  called  for  on  the 
plans,  of  uniform  proportioning  of  the  concrete,  of  breaking  joints  at  the  proper 
places,  of  laying  beams  and  slabs  as  a  monolithic  floor  system,  and  of  determining 
the  hardness  of  the  concrete  before  removing  forms  and  shores. 

The  safety  of  a  well  designed  reinforced  concrete  building  increases  with  age, 
the  concrete  growing  harder  and  the  bond  with  the  steel  becoming  stronger. 

DURABILITY. 

There  is  scarcely  any  class  of  manufacture  which  is  not  now  being  carried  on 
in  a  reinforced  concrete  building.  It  is  adaptable  to  any  weight  of  loading  to  high 
speed  and  heavy  machinery,  as  •well  as  to  light  machine  tools,  and  to  almost  any 
style  of  design. 

Recent  scientific  experiments,  as  well  as  actual  experience,  are  favorable  to 
the  use  of  concrete  under  repeated  and  vibrating  loads. 

The  use  of  concrete  in  brackets  for  supporting  crane  runs,  as  in  the  Bullock 
shop,  Chapter  VII,  is  an  interesting  example  of  severe  application  of  loading. 
Several  concrete  buildings  in  San  Francisco  withstood  the  shock  of  the  earthquake, 
while  those  around  them  of  brick  and  stone  and  wood  were  destroyed. 

13 


While  most  materials  tend  to  rust  or  decay  with  time,  concrete  under  proper 
conditions  continues  to  increase  in  strength  for  months  or  even  for  years. 

Concrete  expands  and  contracts  with  changes  of  temperature.  Its  coefficient 
of  expansion,  that  is,  its  expansion  in  a  unit  length  for  each  degree  of  increase 
in  temperature,  is  almost  identical  with  steel,  and  on  this  account  there  is  no  ten- 
dency of  the  steel  to  separate  from  the  concrete,  and  they  act  together  under  all 
conditions.  As  in  building  with  other  materials,  provision  must  be  made  in  long 
walls  or  other  surfaces  for  the  expansion  and  contraction  due  to  temperature,  by 
placing  occasional  expansion  joints  or  by  adding  extra  steel.  In  factories  of  ordin- 
ary size,  no  special  provision  need  be  made,  as  the  regular  steel  reinforcement  will 
prevent  cracking. 

Special  precautions  are  necessary  for  laying  concrete  in  sea  water.  A  first- 
class  cement  must  be  selected,  rich  proportions  used— at  least  1 :2  14— a  coarse  sand, 
and  well  proportioned  aggregate  which  will  produce  a  dense  impervious  mass. 

FIRE  RESISTANCE. 

Reinforced  concrete  ranks  with  the  best  fireproof  materials,  and  it  is  this 
quality  perhaps  more  than  any  other  which  is  responsible  for  the  enormous  in- 
crease in  its  use  for  factories. 

Intense  heat  injures  the  surface  of  the  concrete,  but  it  is  so  good  a  non-con- 
ductor that  if  sufficiently  thick,  it  provides  ample  protection  for  the  steel  rein- 
forcement, and  the  interior  of  the  mass  is  unaffected  even  in  unusually  severe 
fires. 

For  efficient  fire  protection  in  slabs,  under  ordinary  conditions  the  lower  sur- 
face of  the  steel  rods  should  be  at  least  54  inch  above  the  bottom  of  the  slab.  In 
beams,  girders  and  columns,  a  thickness  of  i^  to  2^  inches  of  concrete  outside 
of  the  steel,  varying  with  the  size  and  importance  of  the  member,  and  the  liability 
to  severe  treatment,  is  in  general  sufficient.  In  columns,  whose  size  is  governed 
by  the  loads  to  be  sustained,  an  excess  of  sectional  area  should  be  provided  so 
that  if,  say,  one  inch  of  the  surface  is  injured  by  fire,  there  will  still  be  enough 
concrete  to  sustain  any  loads  which  may  subsequently  come  upon  it. 

One  of  the  advantages  of  concrete  construction  as  a  fireproof  material  is  that 
the  design  may  be  adapted  to  the  local  conditions.  For  example,  in  an  isolated 
machine  shop  where  scarcely  any  inflammable  materials  are  stored,  it  is  a  waste 
of  money  to  provide  a  thick  mass  of  concrete  simply  to  resist  fire.  On  the  other 
hand,  for  a  factory  or  warehouse  storing  a  product  capable  of  producing  not 
merely  a  hot  fire— a  hot  short  fire  will  not  damage  seriously— but  an  intense  heat 
of  long  duration,  special  provision  may  be  made  by  using  an  excess  area  of  con- 
crete perhaps  two  or  three  inches  thick. 

Actual  fires  are  the  best  test  of  a  material.  One  of  the  most  severe  on  record 
occurred  in  the  Pacific  Coast  Borax  Refinery  described  in  Chapter  IV,  and  the  con- 

14 


crete  there,  as  well  as  in  the  Baltimore  and  San  Francisco  fires,  made  an  excellent 
record. 

The  best  fire  resistance  materials  for  concrete  are  first-class  Portland  cement 
with  quartz  sand  and  broken  trap  rock.  Limestone  aggregate  will  not  stand  the 
heat  so  well  as  trap,  while  the  particles  of  gravel  are  more  easily  loosened  by  ex- 
treme heat.  Neither  of  these  materials,  however,  if  of  good  quality,  need  be 
rejected  for  building  construction  unless  the  demands  are  especially  exacting  and 
the  liability  to  fire  great.  Cinders  make  a  good  aggregate  for  fire  resistance, 
but  the  concrete  made  with  them  is  not  strong  enough  for  reinforced  concrete 
construction  except  in  slabs  of  short  span  or  in  partition  walls. 

The  fire  resistance  of  concrete  increases  with  age,  as  the  water  held  in  the 
pores  is  taken  up  chemically  and  is  evaporated. 

INSURANCE. 

When  reinforced  concrete  first  came  to  the  front  for  factories  and  warehouses, 
the  insurance  companies  hesitated  to  assume  such  buildings  as  first-class  risks. 
However,  examination  and  tests  have  gradually  convinced  the  most  sceptical  of 
their  true  fire  resistance,  until  now  structures  of  this  material  are  sought  after  and 
given  the  lowest  rates  of  insurance. 

Mr.  L.  H.  Kunhardt,  Vice-President  and  Engineer  of  one  of  the  oldest  of  the 
Factory  Mutual  Insurance  Companies,  which  have  for  years  played  a  leading  part 
in  the  development  of  mill  construction,  and  the  science  of  fire  protection  engineer- 
ing and  the  consequent  reduction  of  fire  losses,  presents  in  an  Appendix  to  this 
chapter  (p.  21)  very  instructive  figures  comparing  the  costs  of  insurance  upon  sev- 
eral types  of  factories  for  various  classes  of  manufacture.  Mr.  Kunhardt  also 
indicates  the  means  by  which  concrete  may  be  utilized  in  reducing  even  the  present 
low  rates  of  insurance  upon  buildings  protected  by  efficient  fire  apparatus. 

From  the  statements  there  given  by  so  eminent  an  authority  on  mill  insurance, 
we  may  conclude  that  a  well-designed  reinforced  factory  with  continuous  floors 
(i)  offers  security  agairist  disastrous  fires  and  total  loss  of  structure;  (2)  reduces 
danger  to  contents  by  preventing  the  spread  of  a  fire;  (3)  prevents  damage  by 
water  from  story  to  story ;  (4)  makes  sprinklers  unnecessary  in  buildings  whose 
contents  is  not  inflammable;  (5)  reduces  danger  of  panic  and  loss  of  life  among 
employees  in  case  of  fire. 

STIFFNESS. 

A  reinforced  concrete  building  really  resembles  a  structure  carved  out  of  a 
single  block  of  solid  rock.  It  is  monolithic  throughout.  The  beams  and  girders 
are  continuous  from  side  to  side  and  from  end  to  end  of  the  building,  while  even 
the  floor  slab  itself  forms  a  part  of  the  beams,  and  the  columns  are  also  either  co- 
incident with  them  or  else  tied  to  them  by  their  vertical  steel  rods. 

All  this  accounts  for  the  extraordinary  stiffness  and  solidity  of  a  reinforced 
concrete  structure,  and  differentiates  it  from  timber  construction  where  positive 

15 


joints  occur  over  every  column ;  and  even  from  steel  construction,  in  which  the  de- 
flection is  greater. 

FREEDOM  FROM  VIBRATION. 

This  solidity  and  entire  lack  of  joints,  and  particularly  the  weight  of  the  ma- 
terial, especially  adapts  it  to  both  high  speed  and  heavy  machinery.  The  vibra- 
tions are  deadened  and  absorbed  in  a  way  which  is  impossible  in  steel  structures. 

An  interesting  example  of  this  fact  is  furnished  in  the  Ketterlinus  building 
described  in  Chapter  V,  where  the  vibration  and  jar  in  the  new  concrete  building 
are  remarkably  less  than  in  the  adjacent  steel  and  tile  structure  carrying  the  same 
type  of  machinery. 

VERSATILITY  OF  DESIGN. 

Steel  rods  are  set  in  the  concrete,  to  provide  tensile  strength,  in  such  quantity 
and  location  as  is  needed  for  the  special  loading  for  which  it  is  designed.  Con- 
sequently, spans  can  be  constructed  of  any  reasonable  length,  either  long  or  short, 
and  column  spacing  may  be  adapted  to  the  requirements  of  operation.  Because 
of  the  weight  of  the  concrete,  which  must  itself  be  borne  by  the  strength  of  the 
member,  very  long  beam  and  girder  spans  are  relatively  more  expensive  than  the 
more  ordinary  spans  of  15  or  20  feet.  Similarly,  the  cost  of  floor  slabs  per  square 
foot  increases  appreciably  with  their  span.  These  limitations  are  economical  rather 
than  theoretical,  and  every  design  should  therefore  be  studied  thoroughly  to  pro- 
duce the  best  results  at  least  cost,  and  to  adapt  the  structure  to  the  class  of  man- 
ufacture or  storage  for  which  it  is  intended. 

The  rule  applies  to  reinforced  concrete  as  well  as  to  other  structures,  that  the 
industrial  portion  of  the  plant,  the  arrangement  of  the  machines,  and  of  the  trans- 
mission machinery,  should  be  first  designed  and  the  structure  adapted  to  give  a 
minimum  operating  expense. 

LIGHT. 

A  special  feature  of  reinforced  concrete  construction  is  the  possibility  of 
building  practically  the  entire  wall  of  glass,  so  as  to  afford  a  maximum  amount  of 
light.  Concrete  is  so  strong  that  the  columns  can  be  made  of  small  size  and  the 
windows  carried  by  shallow  beams.  The  window  area  may  thus  cover  a  very  large 
percentage  of  the  wall  surface. 

WATERTIGHTNESS. 

In  some  classes  of  manufacture  where  water  is  freely  used,  as  in  paper  and 
pulp  mills,  it  is  essential  that  the  floors  shall  be  tight  so  that  water  cannot  fall  into 
the  product  on  the  floor  below  or  on  to  the  belting.  In  case  of  fire  a  watertight 
floor  prevents  damage  from  water  to  the  machinery  and  materials  in  the  stories 
below.  A  concrete  floor  with  granolithic  surface  is  practically  impervious  to  water. 

CLEANLINESS. 

Concrete  floors  may  be  laid  on  a  slight  slope  with  a  drain  along  the  sides  of 

16 


the  room  so  as  to  carry  off  all  water  and  permit  flushing  with  the  hose.     Con- 
crete is  vermin  proof. 

RAPIDITY  OF  CONSTRUCTION. 

The  speed  with  which  a  reinforced  concrete  building  can  be  completed  is  due 
in  a  great  measure  to  the  fact  that  there  need  be  no  waiting  for  materials.  Sand 
and  stone  are  always  available ;  Portland  cement  is  now  supplied  by  large  mills  with 
immense  storage  capacity;  and  steel  rods  are  kept  in  stock,  so  that  a  building  can 
be  commenced  as  soon  as  the  plans  are  completed  and  no  delays  need  be  incurred 
in  ordering  special  shapes  and  awaiting  their  shipment  from  the  mills. 

In  general,  under  good  superintendence  the  rate  of  progress  of  a  reinforced 
concrete  factory  may  be  as  fast  as  one-half  story  or  even  one  story  per  week. 

ALTERATIONS. 

Reinforced  concrete  is  not  suitable  for  a  temporary  structure.  It  is  too  dif- 
ficult a  matter  to  tear  it  down.  Radical  changes  in  construction  are  not  readily 
made,  but  holes  may  be  cut  in  walls  and  floors  at  greater  expense  than  in  wood,  but 
without  serious  difficulty. 

HANGING  SHAFTING. 

Provision  may  be  made  for  shafting  by  placing  bolts  or  sockets,  in  the  beams 
to  connect  with  pillow  blocks  for  special  lines  of  shafting,  or  such  connections  may 
be  made  at  regular  intervals  so  that  timbers  or  steel  frames  may  be  bolted  and 
shafting,  or  tracks  for  conveying  material,  supported  at  any  positions  subsequently 
specified. 

BEDDING  MACHINERY. 

All  ordinary  machinery  can  be  directly  bolted  to  the  concrete  floors  by  drilling 
holes  into  them  and  setting  lag-screws  or  through-bolts.  If  a  concrete  foundation 
is  built  for  a  special  machine  or  engine,  it  may  be  bedded  directly  upon  the 
concrete.  To  level  the  machine  on  a  permanent  base,  it  may  be  leveled  an  inch  or 
two  above  the  foundation  proper  and  grouted.  A  dam  of  sand  is  built  around  the 
machine,  and  grout,  made  of  Portland  cement  mortar  in  proportions  one  part  ce- 
ment to  one  or  to  two  parts  of  sand  mixed  to  the  consistency  of  thick  cream,  is 
poured  into  it  so  as  to  run  under  the  casting,  and  then  as  this  mortar  hardens 
it  is  continually  rammed  with  a  rod  to  prevent  shrinkage  and  form  a  solid,  per- 
manent base. 

AUXILIARY  EQUIPMENT. 

Not  only  the  factory  itself,  but  many  of  its  accessories  are  built  of  concrete: 

17 


FOUNDATIONS. 


Foundations  for  engines,  boilers  and  heavy  machines  are  of  course  made  of 
concrete,  this  being  customary-Jong  before  its  introduction  for  building  construction. 
The  method  of  setting  and  bedding  machinery  has  been  referred  to  in  a  preceding 
paragraph. 


POWER  DEVELOPMENT 

Dams  either  of  plain  gravity  section  or  of  reinforced  designs,  flumes,  pen- 
stocks and  wheelpits,  are  all  built  of  this  material.  Every  individual  development 
requires  a  special  design. 


PARTITIONS. 

In  the  factory  itself,  partitions  may  be  made  of  reinforced  concrete  walls  four 
inches  thick,  or  of  concrete  blocks,  as  in  the  Wholesale  Merchants'  Warehouse  at 
Nashville,  Tenn.,  described  in  Chapter  VIII.  For  solid  partition  walls  and  elevator 
wells,  it  is  convenient  to  pour  the  concrete  after  the  floors  are  laid,  and  this  may 
be  done  according  to  the  plan  adopted  by  the  Turner  Construction  Company  in  the 
Bush  Model  Factory  No.  2  (see  Chapter  IX),  by  leaving  a  slot  in  the  floor  at  the 
proposed  location  for  the  partition. 


ROOF. 

Naturally,  the  roof  of  a  reinforced  concrete  building  is  of  the  same  material, 
designed  to  carry  the  weight  of  roof  covering  and  snow  which  may  come  upon  it. 
It  is  advisable  to  cover  with  some  form  of  roofing,  as  the  sun  beating  down  upon 
the  concrete  surface  will  tend  to  crack  it. 

If  the  building  is  erected  with  a  view  to  adding  one  or  more  stories,  it  is  well 
to  build  the  roof  of  wood  or  light  steel  construction  so  that  it  may  be  readily 
taken  down  or  raised. 


TANKS. 

The  making  of  durable  tanks  is  one  of  the  problems  in  many  factories.  This 
is  being  solved  in  numerous  cases  by  the  use  of  reinforced  concrete,  designed 
with  sufficient  steel  to  resist  the  water  pressure.  In  paper  and  pulp  mills  the 
adoption  of  concrete  tanks  is  especially  advisable  because  of  the  frequent  repairs 
and  renewals  required  in  wood  construction.  Sulphuric  acid  and  bleach  liquor  in 
pulp  mills  will  attack  any  known  substance,  even  eating  into  phosphor  bronze. 

18 


Concrete  is  by  no  means  exempt  from  this  action,  but  is  undoubtedly  the  best 
material  except  copper  or  bronze,  which  is  of  course  too  expensive  to  consider. 

Special  attention  should  be  given  to  the  watertightness  of  the  concrete  so  that 
acids  cannot  work  through  it,  and  in  a  small  tank  not  over  10  or  12  feet  high  the 
watertightness  can  be  increased  by  a  coating  of  rich  mortar  on  the  interior, 
troweled  to  a  hard  glassy  surface. 

Limestone  aggregate  should  not  be  used  in  a  tank  to  be  filled  with  acid,  and 
the  steel  reinforcement  should  be  imbedded  at  least  three  inches  or  more.  Some- 
times it  may  be  well  to  provide  an  excessive  thickness  of  concrete  to  allow  for 
subsequent  wear. 

LETTING  THE  CONTRACT. 

The  contract  for  the  construction  of  a  reinforced  concrete  factory  should  be 
let  only  to  responsible  builders  with  practical  experience  in  this  class  of  work. 
A  man  who  has  simply  laid  concrete  foundations  is  not  competent  to  erect  a 
factory  building.  This  matter  of  experience  cannot  be  too  strongly  emphasized, 
since  every  one  of  the  failures  in  reinforced  concrete  can  be  traced  directly  to  poor 
design  or  to  an  ignorance  and  disregard  on  the  part  of  the  builder  of  the  funda- 
mental principles  of  reinforced  concrete  construction. 

If  day  labor  is  employed,  as  in  the  case  of  the  Textile  Machine  Shop,  Chapter 
XI,  it  must  be  under  the  direct  superintendence  of  an  engineer  skilled  in  concrete 
construction. 

The  plan  is  frequently  followed  of  requesting  estimates  from  different  con- 
tractors without  specifying  the  requirements  of  the  design.  As  a  consequence,  the 
man  who  dares  to  figure  with  the  smallest  factor  of  safety,  and  who  thus  would 
build  the  poorest  and  weakest  structure,  presents  the  lowest  bid.  Such  a  possibility 
may  be  precluded  by  having  at  least  the  general  plans  and  specifications  prepared 
in  advance  by  a  competent  engineer  or  architect,  so  that  the  estimates  may  be 
compared  with  fairness. 

Concrete  building  construction  is  frequently  performed  on  the  cost-plus-a- 
fixed-sum  or  cost-plus-a-percentage-basis.  These  methods  are  apt  to  result  in  a 
somewhat  higher  cost  for  the  structure  than  competitive  bidding,  although  they 
offer  less  temptation  to  the  builder. 

Whatever  plan  is  followed,  one  or  more  competent  inspectors  should  be  em- 
ployed by  the  owners  independent  of  the  contractor  to  see  that  the  work  is 
properly  performed  in  all  its  details. 

GROWTH  OF  REINFORCED  CONCRETE  CONSTRUCTION. 

One  of  the  first  uses  of  reinforced  concrete  in  building  construction  was  in 
the  house  erected  by  W.  E.  Ward  in  1872  at  Port  Chester,  N.  Y.  Some  twenty 

19 


years  earlier  than  this,  in  France,  the  first  combinations  of  iron  imbedded  in  con- 
crete were  made  in  a  small  way.  However,  not  until  the  very  end  of  the  last 
century,  since  1895,  has  concrete  been  employed  commercially  in  the  construction 
of  buildings.  Previously  to  this  it  had  attained  a  wide  use  in  foundations,  and  at 
this  time  its  development  was  beginning  for  such  structures  as  dams,  sewers  and 
subways. 

Two  principal  reasons  may  be  offered  for  this  comparatively  slow  growth  fol- 
lowed by  such  marvelous  activity.  In  the  first  place,  Portland  cement  manufac- 
turers, beginning  in  Europe  about  the  middle  of  the  iQth  century  and  in  the 
United  States  about  1880,  finally  produced  a  grade  of  cement  which,  with  the 
inspection  necessary  for  all  structural  materials,  could  be  depended  upon  to  give 
uniform  and  thoroughly  reliable  results;  furthermore,  along  with  the  perfection  of 
the  process  of  manufacture,  the  price  gradually  fell  from  the  high  cost  per  barrel 
in  1880  for  imported  cement,  to  a  figure  for  domestic  Portland  cement  of  equally 
good,  if  not  better,  quality,  at  which  concrete  in  plain  form  could  compete  with 
rough  stone  masonry,  and  with  steel  imbedded  could  compete  with  other  build- 
ing materials. 

In  the  second  place,  theoretical  studies  and  practical  experiments  have  now 
produced  rational  and  positive  methods  for  computing  the  strength  of  concrete 
reinforced  with  steel  so  that  absolute  dependence  can  be  placed  upon  it. 

A  conservative  estimate  places  the  number  of  reinforced  concrete  buildings 
built  in  the  United  States  during  the  year  1906  as  not  less  than  two  hundred,  while 
at  least  as  many  more  have  gone  up  in  concrete  blocks  and  combinations  of  con- 
crete with  other  materials. 

Briefly,  reinforced  concrete  such  as  is  used  for  factory  construction  consists 
of  Portland  cement,  sand,  and  gravel  or  broken  stone,  mixed  with  water  to  a  con- 
sistency that  will  just  flow  sluggishly,  and  in  which  steel  rods  are  imbedded  so  as 
to  produce  an  artificial  stone  with  many  characteristics  of  steel. 

In  the  earlier  stages  of  reinforced  concrete  and  even  up  to  the  present  time, 
many  patents  of  a  more  or  less  fundamental  character  have  been  granted.  These 
have  taken  the  line  of  special  forms  of  reinforcing  metal  as  well  as  methods  of 
design.  The  principal  styles  of  reinforcement  are  illustrated  in  Chapter  XIV. 
While  it  is  not  necessary  to  encroach  on  any  of  these  inventions  in  building,  the 
field  is  worth  careful  consideration,  from  the  viewpoint  of  economy  and  durability, 
as  to  whether  or  not  it  may  be  advisable  to  make  use  of  them. 


20 


APPENDIX. 

FIRE  INSURANCE  ON  FACTORIES  OF  REINFORCED  CONCRETE. 
BY  L.  H.  KUNHARDT,  Vice-President. 

Boston  Manufacturers  Mutual  Fire  Insurance  Co. 

In  consideration  of  the  question  of  insurance  on  reinforced  concrete  factories, 
the  problem  simply  resolves  itself  into  a  determination  of  what  the  fire  and  water 
damage  will  be  in  the  event  of  fire  compared  with  that  in  other  types  of  factory 
buildings. 

For  this  purpose  concrete  factories  may  be  divided  into  two  classes: 

ist.  Those  having  contents  which  are  not  inflammable  or  readily  combustible. 
In  this  class,  if  wooden  window  frames  and  partitions,  etc.,  have  been  eliminated, 
the  building  as  a  whole  becomes  practically  proof  against  fire,  provided  there  are  no 
outside  exposures,  protection  against  which  would  require  special  precautions. 

2nd.  Those  having  contents  which  are  more  or  less  combustible,  and  which 
have  in  their  construction  small  amounts  of  inflammable  material,  such  as  wooden 
window  frames  and  top  floors.  In  this  class  the  burning  of  contents  is  the  cause 
of  damage  to  the  building,  the  extent  of  which  is  determined  by  the  character  of 
the  contents. 

Of  the  two,  the  latter  class  is  the  one  ordinarily  met,  and  with  which  the  ques- 
tion of  insurance  cost  is  therefore  usually  concerned.  The  character  of  the  occu- 
pancy, details  of  construction  and  conditions  of  various  kinds  inside  and  outside  the 
factory,  and  in  the  various  communities,  have  such  direct  bearing  on  rates  that  any 
statement  as  below  of  comparative  cost  must  be  extremely  approximate,  but  perhaps 
of  value  as  showing  somewhat  the  relative  costs.  These  in  the  following  table  are 
made  upon  the  basis  of  a  building  without  a  standard  fire  equipment,  which  con- 
dition is,  however,  now  rare  in  the  case  of  first-class  factories  and  warehouses,  even 
if  of  fireproof  construction. 

CONCRETE  FACTORIES  VS.  THOSE  OF  WOOD  OR  BRICK. 

APPROXIMATE  YEARLY  COST  OF  INSURANCE  PER  $100. 

Exposures,  none ;  area  not  large ;  good  city  department ;  no  private  fire  apparatus 
except  such  as  pails  and  standpipes. 


Brick:Mill  Con- 

Wood  Mill  Con- 

Add    for    Brick 
or  Wood  Bldgs. 
in  Small  Towns 
and  Cities  With- 

General Storehouse  
Wool  Storehouse  
Office  Building  
Cotton  Factory 

All  Concrete. 
Bldg.    Contents. 

20C.          4SC. 

2oc.        35C. 
iSC.        3oc. 

Open   Joists. 
Bldg.    Contents. 
6oc.      looc. 
4oc.        6oc. 
35C.        soc. 

Open   Joists. 
Bldg.    Contents. 

IOOC.         I25C. 

75C.      looc. 

IOOC.         I2SC. 

out  Best  of  Wa- 
ter and  Fire  De- 
partments. 

25C. 
2SC. 
25C. 

Soc. 

Tannery  

20C.           40C. 

75C.      looc. 

IOOC.         IOCC. 

250. 

Shoe  Factory  
Woolen  Mill  

250.       Soc. 

75C.      looc. 

I50C.        200C. 
ISOC.         200C. 

Soc. 
Soc. 

General  Mercantile  Bldg  

35C-       7SC. 

SOC.         IOOC. 

looc.      isoc. 

25C. 

NOTE.—  These  costs  are  based  on  the  absence  of  automatic  sprinklers  and  other  private  fire   protective 

re  not  schedule  rates,  but  may  b 
in  various  parts  of  the  country. 

81 


.— 

appliances  of  the   usual  completely  equipped  building.     They  are  not  schedule  rates,  but  may  be  an  approx 
tion  to  actual  costs  under  favorable  conditions  based  on  examples 


The  table  in  a  general  way  illustrates  the  gain  by  the  use  of  the  better  type  of 
construction,  but  in  factory  work  it  has  long  been  recognized  that  there  is  a  distinct 
hazard  in  the  manufacturing  operations  and  inflammable  contents  which  is  greater 
in  degree  than  in  other  classes  of  property.  The  science  of  fire  protection  with 
automatic  sprinklers  and  auxiliary  apparatus  has  therefore  attained  such  a  degree 
of  perfection  that  the  brick  or  stone  factory  with  heavy  plank  and  timber  floors  is 
obtaining  insurance  at  rates  which  are  lower  than  those  which  are  possible  on  any 
of  the  fireproof  buildings  without  sprinklers.  The  real  reason  for  this  lies  in  the 
fact  that  the  contents,  including  machinery,  stock  in  process,  and  finished  goods, 
constitute  by  far  the  larger  part  of  the  value  of  the  plant,  and  these  the  building 
alone  cannot  be  expected  to  protect  when  a  fire  occurs  within,  except  in  so  far  as 
the  absence  of  combustible  material  in  construction  may  assist  in  so  doing.  Fire 
protection  is  therefore  needed  for  safety  of  contents,  even  if  the  building  itself  is 
practically  fireproof.  • 

As  illustrating  the  value  of  fire  protection,  I  would  state  that  in  the  Boston 
Manufacturers'  Mutual  Fire  Insurance  Company,  and  others  of  the  older  of  the 
Factory  Mutual  Companies,  the  average  cost  of  insurance  on  the  better  class  of 
protected  factories  has  now  for  some  years  averaged,  excluding  interest,  less  than 
seven  (7)  cents  on  each  one  hundred  dollars  of  risk  taken,  and  on  first-class  ware- 
houses connected  with  them,  one-half  this  amount.  These  figures  can  be  compared 
with  the  table  as  illustrating  the  gain  by  the  installation  of  proper  safeguards  for 
preventing  and  extinguishing  fire. 

In  these  same  protected  factories  and  warehouses  the  actual  fire  and  water  loss 
is  less  than  four  (4)  cents  on  each  one  hundred  dollars  of  insurance,  and,  being  so 
small,  it  would  seem  that  they  must  be  almost  impossible  of  reduction,  but  never- 
theless it  is  possible. 

How  can  this  be  accomplished?  This  is  the^wrpblem  of  the  designer  and 
builder  of  the  concrete  factory. 

ist.  By  avoiding  vertical  openings  through  floors — a  common  fault  in  many 
factories  with  wooden  floors.  To  be  a  perfect  fire  cut-off,  a  floor  should  be  solid 
from  wall  to  wall,  with  stairways,  elevators  and  belts  enclosed  in  vertical  fireproof 
walls  having  fire  doors. 

2nd.  By  provision  for  making  floors  practically  waterproof,  that  water  may 
not  cause  damage  on  floors  below  that  on  which  fire  occurs.  Scuppers  of  ample 
size  to  carry  water  from  floors  to  outside  are  an  essential  part  of  the  design.  In 
the  ordinary  factory  with  wooden  floors,  loss  from  water  is  almost  invariably 
excessive  as  compared  with  the  loss  by  actual  fire. 

3rd.  By  making  the  buildings  as  incombustible  as  possible,  thus  reducing  the 
amount  of  material  upon  which  a  fire  may  feed.  Also  by  provision  for  sufficient 
thickness  of  fireproofing  to  thoroughly  insulate  all  steel  work,  the  fireproofing  being 
sufficiently  substantial  that  it  may  not  scale  off  ceilings  or  columns  at  a  fire  or  from 


other  causes,  thus  allowing  failure  of  steel  work,  by  heating  or  deterioration.  An 
owner  is  thus  more  secure  if  the  fire  protection  or  any  parts  of  it  fail  at  a  critical 
moment. 

4th.  By  good  judgment  as  to  the  extent  or  amount  of  fire  protection  required 
in  each  individual  case.  While  the  value  of  the  automatic  sprinkler  is  recognized 
and  the  general  rules  specify  its  installation,  the  Factory  Mutual  Companies  do  not 
require  it  in  the  concrete  building,  except  where  there  is  sufficient  inflammable 
material  in  the  contents  to  furnish  fuel  for  a  fire.  An  essential  feature  of  good 
factory  construction  includes  not  only  consideration  of  the  building,  but  protection 
adequate  to  its  needs  only. 

The  extent  to  which  the  above  is  faithfully  carried  out  will  eventually  be  the 
determining  feature  in  the  cost  of  insurance. 

September  9,   1907. 


CHAPTER  II. 


DESIGN  AND  CONSTRUCTION. 

Concrete  is  an  artificial  stone,  and  if  it  contains  no  steel,  that  is,  if  it  is  not 
reinforced,  it  is  brittle  like  stone.  Just  as  stone  can  be  used  to  support  enormous 
loads,  as  in  foundations,  bridges  and  dams,  provided  it  is  so  placed  as  to  receive 
no  tension  or  pull,  so  can  concrete  stand  heavy  loading  in  compression  with  no 
reinforcement. 

Concrete,  however,  has  the  advantage  of  stone,  because  when  built  in  place, 
steel,  which  is  especially  adapted  for  withstanding  pull,  may  be  introduced  at  just 
the  right  position  in  the  beam  or  other  member  to  take  this  pull.  In  an  ordinary 
beam  the  upper  surface  is  in  compression  and  the  lower  surface  in  tension;  the 
natural  arrangement  of  materials  is  therefore  to  design  the  beam  so  that  the  upper 
part  is  composed  of  concrete,  which  takes  the  compression,  while  steel  is  embedded 
near  the  bottom  to  resist  the  pull  or  tension.  The  concrete  by  surrounding  the 
steel  protects  it  from  rust  and  fire,  and  because  concrete  and  steel  expand  and 
contract  almost  exactly  alike  when  heated  and  cooled,  they  may  be  used  thus  in 
combination  with  no  danger  of  separation  from  changes  in  temperature. 

It  is  evident  that  to  make  a  safe  combination  of  concrete  and  steel,  it  is  neces- 
sary to  know  just  how  much  load  each  can  stand,  and  just  where  the  steel  must 
be  located  to  take  every  bit  of  the  tension  which  may  occur  in  any  part  of  the 
beam.  While  in  a  beam  supported  at  the  ends,  the  pull  is  in  the  bottom  and  the 
principal  steel  must  be  as  near  to  the  bottom  as  is  consistent  with  rust  and  fire  pro- 
tection, on  the  other  hand,  when  the  beam  is  built  into  a  column  or"  into  another 
beam,  a  load  upon  it  produces  also  a  pull  at  the  top  of  the  beam  over  its  supports 
which  tends  to  crack  it  there.  Furthermore,  there  are  other  secondary  stresses  in 
the  interior  of  the  beam,  partly  shear  or  tendency  to  slide  and  partly  tension  or 
pull,  which  must  be  guarded  against  by  locating  steel  rods  in  the  proper  places. 
Hence  the  necessity,  because  of  the  complication  in  the  action  of  the  stresses  even 
in  a  simple  beam,  that  the  designers  have  a  knowledge  of  the  principles  of 
mechanics  and  the  theories  involved. 

It  is  not  the  purpose  of  this  book  to  dwell  upon  the  theory  of  design,  but 
instead  to  give  practical  principles  of  construction  to  supplement  the  theory  which 
can  be  obtained  readily  from  other  sources. 

CEMENT. 

Portland   cement    should   always   be    used    for   concrete    building   construction 

24 


because   it  is   not   only   stronger   than   natural   cement   but   is   more   reliable   and 
hardens  more  quickly. 

The  standard  specifications  adopted  by  the  American  Society  for  Testing 
Materials!  are  generally  adopted  for  important  work  throughout  the  country. 
Brief  specifications  may  be  sufficiently  comprehensive  for  work  of  minor  im- 
portance. 

BRIEF  SPECIFICATIONS  FOR  PORTLAND  CEMENT. 

*A  cement  shall  be  a  first-class  Portland  cement  of  a  standard  brand  bearing 
a.  good  reputation,  sound — i.  e.,  not  liable  to  expansion  or  disintegration, — fine  and 
of  uniform  quality.  It  shall  be  free  from  lumps  and  shall  be  packed  in  sound  bar- 
rels,' or,  if  stored  in  a  dry  place  to  be  used  immediately,  it  may  be  packed  in  stout 
cloth  or  canvas  bags. 

SPECIFICATIONS  FOR  MATERIALS. 

The  following  specifications  are  of  so  general  a  character  as  to  be  applicable 
to  nearly  all  kinds  of  concrete  construction.  Local  requirements  limiting  the 
sizes  of  the  particles  and  giving  further  information  may  be  added. 

SAND.* — The  sand  shall  be  clean  and  coarse,  or  a  mixture  of  coarse  and  fine 
grains  with  the  coarse  grains  predominating.  It  shall  be  free  from  clay,  loam,  mica, 
sticks,  organic  matter,  and  other  impurities. 

SCREENINGS. — *Screenings  or  crusher  dust  from  broken  stone — in  which  term 
is  included  all  particles  passing  a  quarter-inch  screen — by  slightly  altering  the  pro- 
portions of  the  ingredients,  may  be  substituted  for  the  whole  or  a  portion  of  the 
sand  in  such  proportions  as  to  give  a  dense  mixture  and  the  same  relative  volumes 
of  total  aggregates. 

GRAVEL^ — *The  gravel  shall  be  composed  of  clean  pebbles  free  from  sticks  or 
other  foreign  matter  and  containing  no  clay  or  other  materials  adhering  to  the 
pebbles  in  such  quantity  that  it  cannot  be  lightly  brushed  off  with  the  hand  or  re- 
moved by  dipping  in  water.  It  shall  be  screened  to  remove  the  sand,  which  shall 
afterwards  be  remixed  with  it  in  the  required  proportions. 

BROKEN  STONE.J — The  broken  or  crushed  stone  shall  consist  of  pieces  of  hard 
and  durable  rock,  such  as  trap,  limestone,  granite,  or  conglomerate.  The  dust  shall 
be  removed  by  a  quarter-inch  screen,  to  be  afterwards  mixed  with  and  used  as  a 
part  of  the  sand,  if  desired,  except  that  if  the  product  of  the  crusher  is  delivered  to 


*  Paragraphs  designated  by  an  asterisk >re  quoted  from  Taylor  &  Thompson's  "Concrete,  Plain  and 
Reinforced." 

t  These  may  be  obtained  by  addressing  The  Atlas  Portland  Cement  Company. 

J  The  maximum  size  of  stone  for  building  construction  is  customarily  limited  to  i  inch  or  i  ^  inch,  so  that 
the  concrete  may  be  carefully  placed  around  the  steel  and  into  the  corners  of  the  forms.  In  certain  cases  %-mch 
or  %-inch  stone  is  specified,  but  the  larger  size  is  better,  provided  it  can  be  properly  placed. 

25 


the  mixer  so  regularly  that  the  amount  of  dust  (as  determined  by  frequently 
screening  samples)  is  uniform,  the  screening  may  be  omitted  and  the  average  per- 
centage of  dust  allowed  for  in  measuring  the  sand. 

WATER. — The  water  shall  be  free  from  acids  or  strong  alkalies. 

REINFORCING  STEEL.! — *Steel  for  reinforcement  shall  have  an  "ultimate  tensile 
strength  of  55,000  to  65,000  pounds  per  square  inch,  an  elastic  limit  of  not  less  than 
one-half  the  ultimate  strength  (i.  e.,  not  less  than  27,000  pounds)  and  a  minimum 
elongation  in  8  inches  of  1,400,000  divided  by  the  ultimate  strength  per  cent." 
Metal  reinforcement  shall  be  of  such  shape  or  so  anchored  as  suitably  to  assist  its 
adhesion  to  the  concrete. 

PROPORTIONS  OF  MATERIALS. 

In  building  construction,  the  proportions  most  generally  adopted  are  i  part 
cement  to  2  parts  sand  to  4  parts  broken  stone  or  gravel  (this  being  customarily 
indicated  by  the  expression  1:2:4),  or  I  Part  cement  to  21/,  parts  sand  to  5  parts 
broken  stone  or  gravel  (i.  e.,  1:2^:5).  One  part  is  assumed  to  be  equal  to  4 
bags  of  cement,  or  one  barrel,  holding  3.8  cubic  feet ;  thus  proportions  i  :2  -.4.  mean 
one  barrel  (or  4  bags)  Portland  cement,  7.6  cubic  feet  sand  measured  loose  and 
15.2  cubic  feet  of  broken  stone  or  gravel  measured  loose. 

On  a  small  job,  where  tests  cannot  be  made  so  economically  it  is  well  to  be 
conservative  and  require  proportions  i  :2  -.4.  On  the  other  hand,  if  an  engineer  is 
constantly  present,  it  is  often  best  not  to  definitely  specify  the  relative  amount  of 
sand  to  stone,  but  to  permit  the  proportion  to  vary  with  the  material;  thus,  in 
laying  the  concrete  if  there  is  an  excess  of  mortar  the  quantity  of  sand  should  be 
slightly  reduced  and  the  quantity  of  stone  correspondingly  increased,  while  if 
there  is  insufficient  mortar  to  cover  the  stone  and  prevent  stone  pockets,  the  sand 
may  be  increased  and  the  stone  decreased.  The  proportion  of  cement  to  the  sum 
of  the  parts  of  sand  and  stone  may  thus  be  kept  constant. 

MACHINE  MIXING. 

*If  the  concrete  is  mixed  in  a  machine  mixer  a  machine  shall  be  selected  into 
which  the  materials,  including  the  water,  can  be  precisely  and  regularly  propor- 
tioned, and  which  will  produce  a  concrete  of  uniform  consistency  and  color  with 
the  stones  and  water  thoroughly  mixed  and  incorporated  with  the  mortar. 

CONSISTENCY. 

For  building  construction  and  for  other  reinforced  concrete  work  it  is  abso- 
lutely  necessary  that  the  concrete  shall  be  mixed  wet  enough  to  flow  around  and 

*  See  footnote  page  25. 
page  jS/0'  Specificationsfor  hi*h  <*rbon  steel,  see  Taylor  &  Thompson's  "Concrete,  Plain  and  Reinforced," 


thoroughly  imbed  the  steel,  but  it  must  be  no  wetter  than  is  required  to  attain  this 
result.  If  mixed  too  dry,  air  voids  will  be  left  around  the  stone,  and  stone  pockets 
will  appear  on  the  face  of  the  concrete  after  removing  the  forms.  If,  on  the  other 
hand,  too  much  water  is  added,  the  surface  may  have  a  similar  appearance  because 
of  the  water  running  away  from  the  stone. 

PLACING. 

*Concrete  shall  be  conveyed  to  place  in  such  a  manner  that  there  shall  be  no 
distinct  separation  of  the  different  ingredients,  or,  in  cases  where  such  separation 
inadvertently  occurs  the  concrete  shall  be  remixed  before  placing.  Each  layer 
in  which  the  concrete  is  placed  shall  be  of  such  thickness  that  it  can  be  in- 
corporated with  the  one  previously  laid.  Concrete  shall  be  used  so  soon  after 
mixing  that  it  can  be  rammed  or  puddled  in  place  as  a  plastic  homogeneous  mass. 
Any  which  has  set  before  placing  shall  be  rejected.  When  placing  fresh  concrete 
upon  an  old  concrete  surface,  the  latter  shall  be  cleaned  of  all  dirt  and  scum  or 
laitance  and  thoroughly  wet.  Noticeable  voids  or  stone  pockets  discovered  when 
the  forms  are  removed  shall  be  immediately  filled  with  mortar  mixed  in  the  same 
proportions  as  the  mortar  in  the  concrete.  For  horizontal  joints  in  thin  walls,  or 
in  walls  to  sustain  water  pressure,  or  in  other  important  locations,  a  joint  of 
mortar  in  proportions  designated  by  the  engineer  may  be  required. 

SURFACES. 

The  proper  treatment  to  give  a  pleasing  appearance  to  exposed  surfaces  is  one 
of  the  most  difficult  problems  in  concrete  building  construction.  The  surfaces  of 
columns,  beams  and  the  under  sides  of  floors  can  be  made  sufficiently  smooth  by 
carefully  spading,  and  by  seeing  to  it  that  the  mortar  comes  to  the  face  and  that 
the  forms  are  tight  enough  to  prevent  the  mortar  running  out. 

The  treatment  of  outside  surfaces  is  described  and  illustrated  in  Chapter  XIV 
on  Details  of  Construction,  and  the  methods  adopted  in  different  buildings  are 
taken  up  in  the  descriptive  chapters  which  follow. 

FORMS. 

*The  lumber  for  the  forms  and  the  design  of  the  forms  shall  be  adapted  to  the 
structure  and  to  the  kind  of  surface  required  on  the  concrete.  For  exposed  faces 
the  surface  next  to  the  concrete  shall  be  dressed.  Forms  shall  be  sufficiently 
tight  to  prevent  loss  of  cement  or  mortar.  They  shall  be  thoroughly  braced  or 
tied  together  so  that  the  pressure  of  the  concrete  or  the  movement  of  men,  ma- 
chinery or  materials  shall  not  throw  them  out  of  place.  Forms  shall  be  left  in 
place  until  in  the  judgment  of  the  engineer  the  concrete  has  attained  sufficient 


See  footnote  page  25. 

27 


strength  to  resist  accidental  thrusts  and  permanent  strains  which  may  come  upon 
it.    Forms  shall  be  thoroughly  cleaned  before  being  used  again. 

The  time  for  removal  of  forms  is  determined  by  the  weather  conditions  and 
actual  inspection  of  the  concrete.  The  following  approximate  rules  may  be  fol- 
lowed as  a  safe  guide  to  the  minimum  time  for  the  removal  of  forms  :* 

WALLS  IN  MASS  WORK.— One  to  three  days,  or  until  the  concrete  will  bear 
pressure  of  the  thumb  without  indentation. 

THIN  WALLS. — In  summer,  two  days ;  in  cold  weather,  five  days. 

SLABS  UP  TO  Six  FEET  SPAN.— In  summer,  six  days ;  in  cold  weather,  two  weeks. 

BEAMS  AND  GIRDERS  AND  LONG  SPAN  SLABS. — In  summer,  ten  days  or  two 
weeks;  in  cold  weather,  three  weeks  to  one  month.  If  shores  are  left  without 
disturbing  them,  the  time  of  removal  of  the  sheeting  in  summer  may  be  reduced 
to  one  week. 

COLUMN  FORMS. — In  summer,  two  days;  in  cold  weather,  four  days,  provided 
girders  are  shored  to  prevent  appreciable  weight  reaching  columns. 

A  very  important  exception  to  these  rules  applies  to  concrete  which  has  been 
frozen  after  placing,  or  has  been  maintained  at  a  temperature  just  above  freezing, 
In  such  cases  the  forms  must  be  left  in  place  until  after  warm  weather  comes,  and 
then  until  the  concrete  has  thoroughly  dried  out  and  hardened. 

FOUNDATIONS. 

In  a  reinforced  concrete  building,  the  floor  loads  are  carried  by  the  slabs  to 
the  beams  and  girders,  and  thence  to  the  columns,  which  concentrate  the  weight 
upon  small  areas  of  ground.  The  footing  of  each  column  must  therefore  be  spread 
over  a  large  enough  area  of  ground  so  as  not  to  over  compress  the  soil  and  cause 
appreciable  settlement. 

Mr.  George  B.  Francisf  suggests  the  following  loading  for  materials  which 
can  be  clearly  defined,  at  the  same  time  calling  attention  to  the  necessity  for 
varied  and  ample  experience  when  fixing  allowable  pressures  in  any  particular 
case: 

Ledge  rock,  36  tons  per  square  foot. 

Hard  pan,  8  tons  per  square  foot. 

Gravel,  5  tons  per  square  foot. 

Clean  sand,  4  tons  per  square  foot. 

Dry  clay,  3  tons  per  square  foot. 

Wet  clay,  2  tons  per  square  foot. 

Loam,  i  ton  per  square  foot. 


Utintse01'      °nCrete      <""*™<*™>"   ^  Sanfo 
t  Taylor  &  Thompson's  "Concrete,  Plain  and  Reinforced,"  page  473 


C<""*™<*™>"   ^  Sanford  E.   Thompson,  before   National 


To  illustrate  the  use  of  these  rules:  If  a  column  20  inches  square  carries  a 
load  from  above  of  80  tons,  the  footing  over  a  soil  of  dry  sand  must  cover  an 
area  of  8T°  =  20  square  feet;  that  is,  the  footing  must  be  about  4  feet  6  inches 
square. 

Not  only  must  the  area  be  calculated  to  distribute  the  load  over  a  proper 
area  of  soil,  but  the  thickness  of  the  footing  must  be  computed  so  as  to  prevent 
the  column  punching  or  shearing  through  it,  and  a  sufficient  amount  of  rein- 
forcing steel  must  be  placed  in  the  bottom  of  the  concrete  footing  to  prevent  its 
buckling  and  breaking  from  the  concentrated  load  of  the  column.  The  size  of  the 
rods  is  calculated  from  the  bending  moment  produced  by  the  upward  pressure  of 
the  soil  against  the  projection  of  the  footing,  which  may  be  assumed  to  be  a  beam 
supported  upon  a  line  running  through  the  center  of  the  column.  If,  as  is  cus- 
tomary, the  footing  projects  in  both  directions  and  the  rods  run  in  both  directions, 
both  projections  may  be  taken  into  account  as  resisting  the  pressure. 

In  certain  cases  where  a  very  large  footing  is  required,  especially  when  the 
footing  rests  on  piles,  stirrups  may  be  needed  to  resist  shear  or  diagonal  tension, 
as  in  an  ordinary  beam. 

Proportions  of  concrete  for  reinforced  footings  may  be  1 :2l/2  :5,  i.  e.,  one  part 
Portland  cement  to  2^  parts  sand  to  5  parts  broken  stone  or  gravel,  or  the  same 
proportions  may  be  used  as  in  the  building  above  them. 

Foundations  in  dry  ground  which  do  not  require  reinforcement  and  sustain 
only  direct  compression  may  be  laid  in  proportions  of  1 :3 :6  or  i  :3  7.  If  laid  under 
water  the  concrete  should  not  be  leaner  than  i  :2*£  -.5,  while  for  sea  water  con- 
struction a  mixture  at  least  as  rich  as  i  :2 14  is  advisable,  with  very  careful  testing 
of  the  cement  and  aggregates. 

For  a  building  with  no  basement,  foundation  walls  between  the  columns  are 
unnecessary.  The  walls  may  be  started  just  below  the  surface  of  the  ground,  and 
each  wall  slab  will  form  of  itself  a  beam  supported  at  each  end  by  the  column 
foundation.  When  a  basement  is  included  in  the  design,  its  wall  is  apt  to  act  as 
a  retaining  wall  to  resist  the  pressure  of  earth,  and  it  may  be  necessary  to  cal- 
culate the  thickness  and  reinforcement  required  to  resist  the  earth  pressure.  Fre- 
quently, the  bottom  of  the  wall  is  held  by  the  basement  floor,  and  the  top  by  the 
first  floor  of  the  building.  In  this  case  it  may  be  considered  as  a  slab  supported 
at  the  bottom  and  top,  and  the  principal  reinforcing  rods  should  be  vertical  and 
placed  about  one  inch  from  the  interior  face  of  the  wall.  If  there  is  no  support 
at  the  top,  the  footing  may  be  enlarged  by  careful  computation,  and  a  cantilever 
design  made  with  the  principal  tension  rods  vertical  but  near  the  exterior  face  of 
the  wall;  or  the  vertical  slab  may  be  supported  at  the  ends  by  columns  or  but- 
tesses  of  proper  design,  and  the  tension  rods,  computed  to  resist  the  earth  pres- 
sure, run  horizontally  near  the  interior  face. 

For  an  ordinary  cellar  wall  supported  at  bottom  and  top,  a  thickness  of  8 

29 


inches  with  Y&  inch  vertical  rods  about  one  foot  apart  will  be  strong  enough  to 
hold  the  earth,  but  it  is  best  to  actually  compute  the  thickness  and  reinforcement 
for  any  given  case.  Even  if  the  principal  rods  are  vertical,  occasional  horizontal 
rods,  spaced  about  18  inches  or  2  feet  apart,  should  be  placed  in  the  wall  to  tie  it 
together  and  prevent  contraction  cracks. 

BASEMENT  FLOOR. 

The  earth  under  a  basement  floor  must  be  well  drained.  If  necessary,  drains 
of  tile  pipe  or  of  screened  gravel  or  stone  may  be  placed  in  trenches  just  below 
the  concrete,  or  the  entire  level  may  be  covered  with  cinders  or  stone.  If  the  base- 
ment is  below  tide  water  or  ground  water  level,  it  is  not  safe  to  depend  upon  the 
concrete  itself  being  water-tight,  and  a  layer  of  waterproofing  consisting  of  four 
to  six  layers  of  tarred  paper,  mopped  on,  may  be  spread  on  the  concrete  and 
carried  up  in  continuous  sheets  on  the  walls  to  above  water  level,  and  the  whole 
surface  covered  with  another  layer  of  concrete.  In  some  cases,  it  may  be  neces- 
sary to  make  the  concrete  extra  thick,  or  to  add  reinforcement,  to  resist  the 
upward  pressure  of  the  water. 

For  a  basement  floor  in  dry  ground  a  3-inch  or  4-inch  thickness  of  ordinary 
1 13:5  concrete, — that  is,  concrete  composed  of  I  part  Portland  cement  to  3  parts 
sand  to  5  parts  broken  stone  or  gravel, — may  be  laid  and  the  surface  screeded  to 
bring  it  to  the  required  level.  As  it  sets,  this  concrete  should  be  troweled  just  as  the 
wearing  surface  of  a  sidewalk  is  troweled,  but  without  the  mortar  or  granolithic 
finish  which  is  customarily  laid  upon  a  walk.  If  the  floor  is  to  have  a  great  deal 
of  wear  or  trucking,  the  usual  24-inch  or  i-inch  layer  of  i  :2  mortar  may  be  laid 
upon  the  concrete  before  it  has  set,  forming  a  part  of  the  total  thickness  of  4 
inches ;  but  usually  this  is  an  unwarranted  expense  in  a  basement,  as  the  plain 
concrete  will  give  as  good  service. 

It  is  well  in  any  case  to  divide  the  floor  into  blocks,  say,  8  or  10  feet  square, 
so  that  any  shrinkage  cracks  will  come  in  the  joints.  This  is' readily  accomplished 
by  laying  alternate  blocks,  and  then  filling  in  the  intermediate  ones  the  next  day. 

DESIGN  OF  FLOOR  SYSTEM. 

LOADING.— In  designing  a  reinforced  concrete  building,  the  first  considera- 
tion is  the  loading  which  the  various  floors  must  sustain ;  in  other  words, .  the 
strength  which  each  floor  must  have  to  support  the  weights  which  may  come  upon 
it  under  all  conceivable  conditions.  In  a  factory  or  warehouse  it  is  frequently 
possible  to  accurately  calculate  the  maximum  weight  which  will  come  upon  a 
given  area  of  floor.  For  the  very  heaviest  loading  the  problem  is  frequently  the 
simplest,  since  the  heavy  weights  are  apt  to  be  due  to  the  storage  of  merchandise 
whose  weight  per  cubic  foot,  and  therefore  per  square  foot  of  floor,  can  be  readily 

30 


calculated.  Sometimes  the  underside  of  the  floor  must  support  tracks  which 
carry  certain  definite  weights,  and  the  beams  or  girders  must  be  calculated  for 
these  concentrated  loads  in  addition  to  the  uniform  loads  upon  the  floor. 

In  computing  the  strength  of  the  floor  system,  the  weight  of  the  concrete 
/cself  must  always  be  allowed  for.  In  very  long  spans  the  concrete  frequently 
weighs  more  than  the  load  which  will  be  placed  upon  it. 

In  many  cases  the  loading  must  be  assumed  without  actual  computation.  A 
maximum  load  must  frequently  be  selected  to  support  machinery  whose  weight  is 
slight  but  whose  vibrations  require  a  stiff  floor  system. 

The  various  conditions  met  with  in  warehouse  or  factory  construction  may 
thus  necessitate  loadings  varying  from  100  to  500  pounds  per  square  foot  of  floor 
area,  very  wide  limits  and  yet  not  more  than  occur  in  practice.  As  a  guide  to  the 
selection  of  floor  loads,  the  following  values  are  suggested : 

Office  floors 100  pounds  per  square  foot 

Light  running  machinery 150  pounds  per  square  foot 

Medium  heavy  machinery 200  pounds  per  square  foot 

Heavy  machinery 250  pounds  per  square  foot 

Storage  of  parts  or  finished  products,  de- 
pending upon  actual  calculated  loads, 

150  to  500  pounds  per  square  foot 

When  the -loads  are  apt  to  occur  only  over  a  part  of  the  floor,  the  slabs  and 
beams  are  calculated  for  the  full  load,  and  when  computing  the  girders  and 
columns  a  slightly  smaller  load  is  sometimes  used.  For  example,  if  the  slabs  and 
beams  are  figured  for  200  pounds  per  square  foot  of  floor  area,  it  might  be 
assumed  that  the  whole  of  the  total  area  supported  by  a  girder  or  column  would 
never  be  loaded  at  once,  and  the  load  per  square  foot  actually  reaching  the  girder 
and  column  at  any  one  time  would  be  therefore  not  more  than  150  pounds  per 
square  foot  of  floor  area. 

LAYOUT. — The  general  layout  of  the  beams  and  girders  and  columns  depends 
upon  the  loading,  the  uses  to  which  the  building  is  to  be  put,  and  the  ground 
area.  Frequently  in  a  large  building,  it  will  be  worth  while  to  require  the  en- 
gineer to  make  several  comparative  estimates  with  different  spacings  of  columns 
and  sizes  of  panels,  so  as  to  determine  that  which  is  most  economical  consistent 
with  the  floor  area  required  for  the  machinery. 

Common  spacings  of  columns  in  a  reinforced  concrete  building  are  from  12 
feet  to  20  feet.  Longer  spans  are  not  usually  so  economical,  but  may  frequently  be 
necessary  to  give  the  floor  space  required  for  machinery  or  storage.  Several  of 
the  buildings  described  in  the  chapters  which  follow  are  designed  for  long  spans, 
but  it  will  be  noticed  that  very  heavy  beams  and  girders  are  required  for  them. 

Taking  a  general  case,  if  the  spacing  of  the  columns  is  20  feet  each  way,  the 
columns  are  connected  by  girders  running  in  one  direction,  usually  the  long  way 

31 


of  the  building,  and  into  these  girders  run  beams  spaced  6  feet  to  8  feet  apart. 
Other  arrangements  will  suggest  themselves  from  the  descriptive  chapters  which 
follow. 

FLOOR  SLABS.— The  thickness  and  reinforcement  of  the  floor  slabs  is  de- 
termined by  the  distance  between  the  beams,  and  by  the  loading  which  will  conu 
upon  them.  The  most  usual  thicknesses  are  3^2  inches  to  5  inches,  with  reinforce- 
ment calculated  from  the  bending  moment  produced  by  the  loads.  An  economical 
quantity  of  steel  is  apt  to  be  from  0.8  per  cent,  to  i  per  cent,  of  the  sectional  area 
of  the  slab  above  the  steel. 

A  few  rods  are  usually  placed  at  right  angles  to  the  main  bearing  rods  of  the 
slab  to  assist  in  preventing  contraction  cracks,  and  these  also  add  to  the  strength 
of  the  slab. 

In  a  factory  or  warehouse  the  most  economical  floor  surface  is  generally  a 
granolithic  finish,  consisting  of  a  layer  of  i  :2  mortar  about  three-quarter  inch 
thick,  spread  upon  the  surface  of  the  concrete  slab  before  it  has  begun  to  set,  and 
troweled  to  a  hard  finish  just  like  a  concrete  sidewalk. 

Machines  are  readily  bolted  to  the  concrete  by  drilling  small  holes  in  the 
concrete  at  the  proper  points  for  the  standards  and  grouting  the  lag  screws  in 
place,  or  else  bolting  them  through  the  slab. 

If  for  any  reason  a  wood  floor  is  required,  stringers  may  be  laid  upon  the 
top  of  the  concrete  and  spaces  left  between  them  or  filled  with  cinders  or  with 
cinder  concrete. 

BEAMS  AND  GIRDERS.— As  already  indicated,  the  sizes  and  reinforce- 
ment of  the  beams  and  girders  must  be  accurately  computed  by  one  who  thor- 
oughly understands  the  theories  involved  in  reinforced  concrete  design.  Even 
if  tables  are  used  the  designer  must  have  a  knowledge  of  mechanics  and  of  the 
way  in  which  the  stresses  act. 

It  is  a  simple  matter  to  determine  the  amount  of  steel  required  in  the  bottom 
of  the  beam  to  sustain  the  pull  due  to  a  given  loading,  but  while  this  is  an  im- 
portant determination  it  is  by  no  means  the  only  one. 

The  weak  points  in  reinforced  concrete  structures  are  not  usually  due  to  in- 
sufficient steel  for  tension,  but  more  often  to  an  ignorance  of  other  smaller  details 
not  less  important.  It  is  thus  absolutely  dangerous,  and  in  fact  criminal,  for  a 
novice  to  design  or  pass  upon  drawings  for  a  reinforced  concrete  structure. 

The  design  of  reinforced  concrete  beams  and  girders  involves  the  following 
studies: 

(0  The  bending  moment  due  to  the  live  and  dead  loads,  this  involving  the 
selection  of  the  proper  formula  for  the  computation. 

(2)  Dimensions  of  beams  which  will  prevent  an  excessive  compression  of 
the  concrete  in  the  top  and  which  will  give  the  depth  and  width  which  is  other- 
wise most  economical. 


(3)  Number  and  size  of  rods  to  sustain  tension  in  the  bottom  of  the  beam. 

(4)  Shear  or  diagonal  tension  in  the  concrete. 

(5)  Value  of  bent-up  rods  to  resist  shear  or  diagonal  tension. 

(6)  Stirrups  to  supplement  the  bent-up  rods  in  assisting  to  resist  the  shear 
or  diagonal  tension. 

(7)  Steel   over   the   supports   to  take   the   tension   due   to   negative   bending 
moment. 

(8)  Concrete  in  compression  at  the  bottom  of  the  beam  near  the  supports 
due  to  negative  bending  moment. 

(9)  Horizontal  shear  under  flange  of  slab. 

(10)     Shear  on  vertical  planes  between  beams  and   flanges, 
(u)     Distance  apart  of  rods  to  resist  splitting. 

(12)  Length  of  rods  to  prevent  slipping. 

(13)  End  connections  at  wall. 

Although  it  is  not  the  province  of  this  book  to  go  into  the  mathematical 
treatment  of  these  various  points,  many  of  them  are  as  yet  so  inadequately  treated 
in  literature  on  the  subject  that  it  will  be  advisable  to  touch  upon  them  in  a 
general  way. 

BENDING  MOMENT. — The  first  important  computation  for  an  engineer 
to  make  is  the  determination  of  the  bending  moment.  In  a  beam  which  is  merely 
supported  at  the  ends  like  a  steel  beam  or  a  timber  girder  resting  upon  columns, 
the  calculation  is  very  simple,  and  can  be  readily  made  by  drawing  a  load  diagram, 
or  in  the  simple  case  of  a  uniformly  distributed  load  by  using  the  formula 

M  =  ysWL  (i) 

in  which 

M  =  bending  moment  in  inch  pounds. 

W  =1  total  load  in  pounds  supported  by  the  beam  or  girder  (including  the 
dead  load). 

L  =  length  of  span  of  beam  or  girder  in  inches. 

When  a  beam  is  continuous  or  is  more  or  less  fixed  at  the  end?,  as  is  the  case 
in  reinforced  concrete  construction,  where  the  entire  floor  system  is  laid  as  one 
unit,  the  conditions  are  changed,  the  stress  in  the  center  of  the  beam  is  less,  and 
there  is  also  a  reverse  action,  termed  the  negative  bending  moment,  at  the 
supports. 

It  is,  therefore,  conservative  practice  to  use  in  general  for  slabs,  and  for 
beams  and  girders  which  are  built  into  each  other  or  into  heavy  columns,  the 
formula 

M=  i/io  WL  (2) 

For  the  end  spans,  that  is,  for  beams  and  girders  running  into  a  wall,  formula   (i) 
is  generally  used  instead. 

These  values  for  the  bending  moment,  as  stated,  are  conservative  and  eventually 
it  will  probably  be  considered  safe  to  slightly  increase  them. 

33 


The  negative  bending  moment  at  the  end  of  the  beams  must  be  provided  for 
by  steel  rods  carried  over  the  top  of  the  support  for  tension,  and  by  a  sufficient 
quantity  of  concrete  at  the  bottom  of  the  beam  near  the  support  to  take  the 
compression.  Using  formula  (i)  or  (2)  for  the  design  at  the  center  gives  a  very 
stiff  beam  so  that  for  the  negative  moment  at  the  ends  it  is  safe  to  use 
— M  =  1/12  WL 

Since  the  pull  in  the  bottom  of  the  beam  decreases  toward  the  supports  a  part 
of  the  tension  rods  may  be  bent  up  on  an  incline  from  about  one-quarter  points 
in  the  beam,  if  the  load  is  uniformly  distributed,  and  pass  horizontally  through  the 
top  of  the  beam  at  the  supports.  The  rods  must  extend  over  the  supports  for  a 
sufficient  distance  to  receive  the  compressive  stress  there,  or  must  be  firmly  con- 
nected with  corresponding  rods  in  the  adjacent  bay.  The  total  steel  in  the  top 
must  be  sufficient  to  resist  the  tension  due  to  the  negative  moment. 

In  slabs  it  is  good  practice  to  bend  up  all  of  the  rods  at  the  quarter  points 
toward  the  supports. 

STEEL.— City  building  laws  are  apt  to  limit  the  tension  in  steel  to  16,000 
pounds  per  square  inch.  Many  engineers  adopt  the  value,  slightly  more  con- 
servative and  therefore  preferable,  of  14,000  pounds  per  square  inch. 

CONCERTE. — If  the  concrete  is  made  of  first-class  materials  mixed  not 
leaner  than  i  part  cement  to  2  parts  sand  to  4  parts  stone,  so  as  to  have  a  com- 
pressive strength  of  at  least  2,000  pounds  per  square  inch  at  the  age  of  28  days,  a 
value  as  high  as  600  pounds  per  square  inch  for  the  extreme  fiber  compression  in 
beams  and  slabs  may  be  used  with  safety,  provided  the  computation  is  based  on 
what  is  termed  the  straight  line  distribution  of  stress,  and  the  ratio  of  the  modulus 
of  elasticity  of  steel  to  concrete  is  taken  at  15.  To  guard  against  the  possibility  of 
poor  workmanship,  building  departments  frequently  fix  a  limit  of  500  pounds  per 
square  inch. 

In  computing  the  compression,  the  beam  is  usually  considered  of  T-section, 
that  is,  the  slab  for  a  certain  distance  on  each  side  of  the  beam  is  assumed  to  act 
as  part  of  the  beam.  The  width  of  slab  to  use  in  computing  the  beam  is  usually 
taken  from  one-fifth  to  one-third  the  span  of  the  beam,  and  not  more -than  two- 
thirds  the  distance  between  beams.  In  order  to  take  advantage  of  the  strength 
of  the  slab,  it  is  absolutely  necessary  that  the  concrete  be  laid  in  the  slabs  at  the 
same  time  as  in  the  beams,  so  as  to  prevent  any  joint  between  them.  The  disre- 
gard of  this  important  rule  has  contributed  to  more  than  one  failure  of  reinforced 
concrete. 

STIRRUPS.— Besides  the  ordinary  compression  and  pull  in  a  beam,  there  are 
secondary  stresses  of  shear  or  diagonal  tension,  which,  if  not  provided  for,  will 
produce  diagonal  cracks.  These  will  run  in  a  general  direction  from  the  bottom 
of  the  beam  near  the  supports  on  an  incline  toward  the  top  of  the  beam,  and  may 
cause  the  beam  to  fail.  To  prevent  this  cracking,  unless  the  beam  is  so  wide  that 

34 


the  concrete  can  take  the  whole  of  the  stress  without  exceeding  60  pounds  per 
square  inch  in  shear,  vertical  or  inclined  steel  bars,  of  sizes  accurately  computed, 
must  be  placed.  The  bent-up  tension  rods  take  care  of  a  part  of  this  shear,  or 
diagonal  tension,  but  if  these  are  not  sufficient,  stirrups,  which  are  usually  made 
in  the  form  of  a  U,  must  be  inserted  at  the  proper  locations  to  take  the  remainder. 

COLUMNS. 

The  most  important  of  all  the  members  of  the  building  are  the  columns,  for 
if  a  column  fails  the  entire  building  is  liable  to  go  down. 

If  columns  as  ordinarily  built  in  building  construction  are  made  of  1:2:4 
proportions,  it  is  safe  in  an  ordinary  building  to  allow  a  direct  compressive 
strength  of  450  pounds  per  square  inch,  provided  the  columns  are  at  least  12 
inches  square.  A  customary  manner  of  designing  is  to  figure  the  entire  com- 
pression upon  the  concrete  to  the  full  size  of  the  column,  but  to  place  four  or 
possibly  six  rods  of  5^-inch  or  fy  inch  diameter  near  the  corners  or  sides  of  the 
column,  with  %-inch  wire  loops  around  these  rods  at  occasional  intervals  in  the 
height,  say,  from  8  to  12  inches  apart. 

Vertical  steel  rods  of  larger  size  may  be  introduced  when  it  is  necessary  to 
decrease  the  size  of  the  columns.  These  may  be  computed  to  bear  a  portion  of 
the  compressive  load,  but  they  cannot  be  figured  at  their  full  safe  value  of  16,000 
pounds  per  square  inch  because  they  have  a  different  modulus  of  elasticity  and 
compressive  strength  from  concrete  and  can  only  shorten  the  same  amount  as 
the  concrete.  Under  ordinary  circumstances,  therefore,  they  cannot  be  assumed 
to  bear  more  than  the  safe  compressive  stress  in  the  concrete  times  the  ratio  of 
elasticity  of  steel  to  concrete,  or  about  7,000  pounds  per  square  inch.  Because  of 
this  small  amount  of  compression  which  they  can  bear,  it  is  always  cheaper  to 
enlarge  the  column  rather  than  to  insert  steel  of  larger  diameter  to  assist  in  taking 
the  load. 

Another  means  of  increasing  the  strength  of  the  column  is  to  use  a  richer 
mixture.  This  is  legitimate  provided  the  same  mixture  is  carried  up  through 
the  floor  system  at  Jhe  column  so  that  there  will  be  no  weak  places.  By  using 
proportions  I  :i  :3  a  safe  working  compression  in  the  concrete  of  700  pounds  per 
square  inch  may  be  adopted. 

Hooped  columns,  that  is,  columns  reinforced  with  bands  placed  near  to- 
gether or  with  spirals,  are  frequently  adopted  to  reduce  the  size  of  the  column. 
It  is  a  serious  question  in  the  minds  of  conservative  engineers  as  to  whether  it  is 
good  practice  to  assume  that  a  large  proportion  of  the  load  can  be  borne  by 
such  hoops.  Although  tests  have  shown  that  hooped  columns  have  a  high  ulti- 
mate strength,  these  same  tests  prove  that  the  concrete  within  the  hoops  is  over- 
strained before  the  hoops  begin  to  take  any  of  the  tension  which  must  reach  them 
in  order  to  strengthen  the  columns. 

35 


Composite  columns,  which  are  virtually  steel  columns  surrounded  by  con- 
crete, have  been  used  in  a  number  of  buildings.  An  instance  of  this  is  the  Ketter- 
linus  building,  described  in  Chapter  V.  This  construction,  although  more  ex- 
pensive than  plain  concrete,  is  advantageous  where  the  floor  space  is  so  valuable 
that  the  dimensions  of  the  columns  must  be  kept  small. 

WALLS. 

The  walls  of  reinforced  concrete  factories  are  sometimes  built  up  with  the 
columns,  but  it  is  generally  considered  more  economical  to  erect  the  skeleton 
structure  and  fill  in  the  wall  panels,  as  described  in  Chapters  VI  and  IX. 

Slots  in  the  columns  are  made  by  nailing  a  strip  on  the  inside  of  the  column 
forms.  In  this  way  the  panels  are  mortised  into  the  columns. 

Ordinary  concrete  walls  require  light  reinforcement  to  prevent  shrinkage  and 
give  them  stiffness  while  setting.  All  that  is  required  for,  say,  a  4-inch  or  6-inch 
wall  are  %-inch  rods  spaced  from  12  to  24  inches  apart,  according  to  the  size  and 
importance  of  the  wall.  At  window  and  door  openings  a  larger  amount  of  rein- 
forcement is  of  course  necessary,  and  in  these  cases  the  amount  of  steel  must  be 
calculated  just  as  though  the  lintels  were  reinforced  concrete  beam's. 

ROOFS. 

Reinforced  concrete  roofs  are  designed  like  floors.  A  roof  load  commonly 
assumed  in  temperate  climates,  to  provide  for  roof  covering,  snow  and  wind  pres- 
sure, is  40  pounds  per  square  foot,  in  addition  to  the  weight  of  the  concrete  itself. 

It  is  not  safe  to  assume  that  the  concrete  roof  of  itself  will  be  water-tight 
unless  special  provision  is  made  in  the  construction.  Although  tanks  and  walls 
can  readily  be  made  to  hold  water,  a  roof  is  under  extraordinarily  disadvantageous 
conditions  because  of  the  rays  of  the  sun.  Usually,  therefore,  a  tar  and  gravel 
or  other  form  of  roof  covering  must  be  provided. 

CONSTRUCTION. 

The  details  of  construction  are  treated  at  length  for  individual  buildings  in 
the  chapters  which  follow.  Chapter  XIV  also  takes  up  many  special  points  and 
treats  as  well  of  different  methods  of  reinforcing. 

A  reinforced  concrete  building  must  have  careful  inspection  while  in  process 
of  erection,  the  special  points  to  be  observed  being: 

(1)  Exact  proportioning  of  materials. 

(2)  Placing  the  concrete  so  as  to  prevent  separation  of  ingredients. 

(3)  Placing  concrete  to  avoid  joints  except  where  called  for. 

(4)  Exact  placing  and  imbedding  of  the  reinforcement. 

(5)  Proper  securing  of  the  forms. 

(6)  Maintenance  of  the  forms   in  position   until   the  concrete  is   sufficiently 
strong. 

36 


CHAPTER  III. 


CONCRETE  AGGREGATES.* 

The  term  "aggregate"  includes  not  only  the  stone,  but  also  the  sand  which 
is  mixed  with  cement  to  form  either  concrete  or  mortar;  in  other  words,  it  is  the 
entire  inert  mineral  material.  This  definition,  now  generally  accepted,  has  re- 
placed the  one  restricting  the  term  to  the  coarse  aggregate  alone.  It  is  the  object 
of  this  chapter  to  enumerate  the  general  principles  which  should  be  followed  in 
the  selection  of  sand  and  stone  for  mortar  and  concrete,  and  to  describe  briefly 
the  method  of  testing  aggregates  and  determining  proportions  which  the  author 
has  found  to  give  good  results  in  practice. 

At  the  outset,  it  may  be  said  that  a  concrete  of  fair  quality,  if  rich  enough  in 
cement,  can  be  made  with  nearly  any  kind  of  mineral  aggregate,  but  there  is, 
nevertheless,  a  wide  variation  in  the  results  produced.  For  the  fine  aggregate,  sand, 
broken  stone,  screenings,  pulverized  slag  or  the  fine  material  from  cinders  may  be 
used  separately  or  in  combination  with  each  other.  For  the  coarse  aggregate, 
broken  stone,  gravel,  screened  gravel  slag,  crushed  lava,  shells,  broken  brick,  or 
mixtures  of  any  of  these  may  be  employed.  However,  the  very  fact  of  the 
adaptability  of  concrete  to  so  wide  a  range  of  materials,  every  one  of  which  really 
consists  of  a  large  class  varying  in  size,  shape  and  composition,  tends  to  blind 
one  to  the  economies  which  often  may  be  effected  and  the  improvement  in  quality 
which  almost  always  will  result  by  a  careful  selection  and  proportioning  of  the 
aggregates. 

In  many  cases,  especially  where  the  cost  of  Portland  cement  is  low,  it  may  be 
cheaper  to  use  whatever  materials  are  nearest  at  hand,  and  insure  the  quality  of 
the  concrete  or  mortar  by  making  it  excessively  rich  in  cement.  If  the  structure 
is  small  and  of  little  importance  this  course  is  properly  followed,  but,  on  the 
other  hand,  if  a  large  amount  of  concrete  is  to  be  laid,  and  especially  if  the  process 
is  to  be  carried  on  in  a  factory,  as  in  concrete  block  manufacture,  it  pays  from 
the  standpoints  of  both  quality  and  economy  to  use  great  care  in  the  selection  of 
the  aggregates,  as  well  as  of  the  cement,  and  to  provide  means  for  maintaining 
uniformity. 

To  illustrate  the  variation  which  different  aggregates  may  produce  even  when 
they  are  mixed  with  cement  in  the  same  proportions,  the  author  has  selected 
a  few  comparative  tests  of  mortar  and  concrete. 


Read  by  the  author  before  the  National  Association  of  Cement  Users,  June,  1906. 
37 


EFFECT  OF  DIFFERENT  AGGREGATES  UPON  THE 
STRENGTH  OF  MORTAR  AND  CONCRETE. 

Tests  by  Mr.  Rene  Feret,*  of  France,  with  mortar  made  from  different 
natural  sands  show  a  surprising  variation  in  strength,  which  is  evidently  due 
simply  to  the  fineness  of  the  sand  of  which  the  different  specimens  are  composed. 
Selecting  from  his  results  proportions  i  :2^  by  weight — that  is,  I  part  cement  to 
2l/2  parts  sand — and  converting  his  results  at  the  age  of  five  months  from 
French  units  to  pounds  per  square  inch,  the  average  tensile  strength  of  Portland 
cement  mortar  made  with  coarse  sand  is  421  pounds  per  square  inch,  with  medium 
sand  368  pounds  per  square  inch,  and  with  fine  sand  302  pounds  per  square  inch. 
In  the  crushing  strength,  usually  the  most  important  consideration,  the  difference 
is  even  more  marked.  In  round  numbers,  at  the  age  of  five  months  the  mortar 
of  coarse  sand  gave  5,200  pounds  per  square  inch;  of  the  medium  sand,  3,400 
pounds  per  square  inch,  and  of  the  fine  sand  1,900  pounds  per  square  inch.  Note 
that  the  different  sands  were  not  artificially  prepared,  but  were  taken  from  the 
natural  bank  and  correspond  to  those  which  every  day  are  being  used  for  concrete 
and  mortar. 

The  effect  of  different  mixtures  of  the  same  kind  of  material  is  shown  by  tests 
made  by  the  author  in  1905.!  By  varying  the  sizes  of  the  particles  of  the  aggre- 
gates, but  using  in  all  cases  stone  from  the  same  ledge  and  the  same  proportion 
of  cement  to  total  aggregate  by  weight,  namely,  1:9  (or  approximately  1:3:6),  it 
was  found  possible  to  make  specimens  the  resulting  strengths  of  some  of  which 
were  two  and  a  half  times  the  strength  of  others. 

The  effect  of  the  hardness  or  strength  of  the  stone  used  for  the  coarse  aggre- 
gate is  shown  in  tests  of  George  W.  Rafter,^  which,  for  proportions  about  1 :26l/2, 
gave  50  per  cent,  greater  compressive  strength  of  concrete  where  the  coarse 
aggregate  was  a  hard  sandstone  than  with  similar  proportions  where  a  shale  was 
substituted.  In  some  of  his  tests  the  harder  stone  gave  a  concrete  even  double 
the  strength  of  the  concrete  with  softer  stone. 

GENERAL  PRINCIPLES  FOR  SELECTING  STONE. 

The  quality  of  concrete  is  affected  by  the  hardness  of  the  stone,  the  shape  of 
the  particles,  the  maximum  size  of  the  particles  and  the  relative  sizes  of  the  par- 
ticles. 

If  broken  stone  is  used,  and  there  is  an  opportunity  for  choice,  the  best  is 
that  which  is  hard;  with  cubical  fracture;  with  particles  whose  maximum  size  is  as 
large  as  can  be  handled  in  the  work;  with  the  particles  smaller  than,  say,  ^  inch, 

*  Taylor  &  Thompson's  "Concrete,  Plain  and  Reinforced,"  page  136. 
t  Proceeding  American  Society  of  Civil  Engineers,  March,  1907. 
t  Second  Report  on  Genesee  River  Storage  Project,  1894. 


screened  out  to  be  used  as  sand;  and  with  the  sizes  of  the  remaining  coarse  stone 
varying  from  small  to  large,  the  coarsest  predominating. 

If  gravel  is  used  it  must  be  clean.  The  maximum  size  of  particles  should 
be  as  large  as  can  be  handled  in  the  work ;  grains  below,  say,  J4  inch,  should  be 
screened  out  to  be  used  as  sand,  and  the  size  of  the  stone  should  vary,  with  the 
coarsest  predominating. 

As  already  stated,  the  size  of  the  coarsest  particles  of  stone  should  be  as 
large  as  can  be  handled  in  the  work.  This  is  because  the  strength  of  the  concrete 
is  thereby  increased  and  a  leaner  mixture  can  be  used  than  with  small  stone.  In 
mass  concrete  the  stones  if  too  large  are  liable  to  separate  from  the  mortar  unless 
placed  by  hand  or  derrick,  as  in  rubble  concrete,  and  a  practical  maximum  size 
is  2^  or  3  inches.  In  thin  walls,  floors  and  other  reinforced  construction,  a  i-inch 
maximum  size  is  generally  as  large  as  can  be  easily  worked  between  the  steel. 
In  some  cases  where  the  walls  are  very  thin,  say  3  or  4  inches,  a  ^4-inch  maximum 
size  is  more  convenient  to  handle. 

It  is  a  little  more  trouble  but  almost  always  best  to  screen  out  the  sand  from 
gravel  or  the  fine  material  from  crusher  stone,  and  then  remix  it  in  the  propor- 
tions required  by  the  specifications,  for  otherwise  the  proportions  will  vary  at 
different  points,  and  one  must  use  and  pay  for  an  excess  of  cement  to  balance 
the  lack  of  uniformity. 

If  the  gravel  is  used,  it  is  absolutely  essential  that  it  shall  be  clean,  because 
if  clay  or  loam  adheres  to  the  particles,  the  adhesion  of  the  cement  will  be  de- 
stroyed or  weakened.  Tests  of  the  Boston  Transit  Commission*  give  an  average 
unit  transverse  strength  of  605  pounds  per  square  inch  for  concrete  made  with 
clean  gravel  as  against  446  pounds  per  square  inch  when  made  with  dirty  gravel. 

COMPARATIVE  VALUES  OF  DIFFERENT  STONE. 

Different  stones  of  the  same  class  vary  so  widely  in  texture  and  strength 
that  it  is  impossible  to  give  their  exact  comparative  values  for  concrete.  A  com- 
parison by  the  author  of  a  large  number  of  tests  of  concrete  made  with  different 
kinds  of  stone  indicates  that  the  value  of  a  broken  stone  for  concrete  is  largely 
governed  by  the  actual  strength  of  the  stone  itself,  the  hardest  stone  producing 
the  strongest  concrete.  This  forms  a  valuable  guide  for  comparing  different 
stones.  Comparative  tests  indicate  that  different  stones  in  order  of  their  value 
for  concrete  are  approximately  as  follows:  (i)  Trap,  (2)  granite,  (3)  gravel,  (4) 
marble,  (5)  limestone,  (6)  slag,  (7)  sandstone,  (8)  slate,  (9)  shale,  (10)  cinders. 
Although,  as  stated  above,  the  wide  difference  in  the  quality  of  the  stone  of  any 
class  makes  accurate  comparisons  impossible— and  this  difficulty  is  increased  by 
the  fact  that  the  proportions  and  age  of  the  specimens  affect  their  relative  value — 


Seventh  Report  of  Boston  Transit  Commission,  1901,  page 


an  approximate  estimate  drawn  from  actual  tests  gives  the  value  for  concrete  of 
good  quality  sandstone  as  not  more  than  three-fourths  the  value  of  trap,  and  the 
value  of  slate  as  less  than  half  that  of  trap.  Good  cinders  nearly  equal  slate  and 
shale  in  the  strength  of  concrete  made  with  them. 

The  hardness  of  the  stone  grows  in  importance  with  the  age  of  the  concrete. 
Thus  gravel  concrete,  because  of  the  rounded  surfaces,  at  the  age  of  one  month 
may  be  weaker  than  a  concrete  made  with  comparatively  soft  broken  stone;  but 
at  the  age  of  one  year  it  may  surpass  in  strength  the  broken  stone  concrete,  be- 
cause as  the  cement  becomes  hard,  there  is  greater  tendency  for  the  stones  them- 
selves to  shear  through,  and  the  hardness  of  the  gravel  stones  thus  comes  into 
play.  Gravel  makes  a  dense  mixture,  and  if  much  cheaper  than  broken  stone,  can 
usually  be  substituted  for  it. 

A  flat  grained  material  packs  less  closely  and  generally  is  inferior  to  stone  of 
cubical  fracture. 

GENERAL  PRINCIPLES  FOR  SELECTING  SAND.     . 

The  only  characteristics  of  sand  which  need  be  considered  are  the  coarseness 
of  its  grains  and  its  cleanness.  These  qualities  affect  the  density  of  the  mortar 
produced,  and  therefore  the  test  of  the  volume  of  mortar,  or  "yield"  determines 
which  of  two  or  more  sands  is  best  graded.  The  "yield"  or  "volumetric"  test  is 
considered  by  the  author  of  greater  value  for  quick  results  than  all  others  put 
together.  The  methods  of  employing  it  are  described  farther  along  in  the  paper. 

The  best  sand  is  that  which  produces  the  smallest  volume  of  plastic  mortar 
when  mixed  with  cement  in  the  required  proportions  by  weight. 

A  high  weight  of  sand  and  a  corresponding  low  percentage  of  voids  are  in- 
dications of  coarseness  and  good  grading  of  particles ;  but  because  of  the  impos- 
sibility of  establishing  uniformity  in  weighing  or  measuring,  they  are  merely  gen- 
eral guides  which  cannot  under  any  conditions  be  taken  as  positive  indications  of 
true  relative  values.  The  various  characteristics  of  sands  are  separately  considered 
in  the  following  paragraphs : 

WEIGHT  OF  SAND. — A  heavy  sand  is  generally  denser,  and  therefore  bet- 
ter than  a  light  sand.  However,  this  is  not  a  positive  sign  of  worth,  because  the 
difference  in  moisture  may  affect  the  weight  by  20  per  cent.,  and  when  weighed 
dry  the  results  are  not  comparable  for  mortars,  since  fine  sand  takes  more  water 
than  coarse. 

As  an  illustration  of  the  variation  in  weight  of  natural  sands  having  different 
moisture,  the  author  found  that  the  weight  per  cubic  foot  of  Cowe  Bay  sand,  which 
dry  averaged  103  pounds,  when  placed  out  of  doors  and  after  a  rain  shoveled  into  a 
measure  and  weighed  in  exactly  the  same  way  (although  it  was  allowed  to  drain 
for  two  days)  averaged  83  pounds. 

40 


VOIDS  IN  SAND.— The  voids,  like  the  weight,  are  so  variable  in  the  same 
sand,  because  of  different  percentages  of  moisture  and  different  methods  of  hand- 
ling, that  their  determination  is  of  but  slight  value.  In  the  Cowe  Bay  sand  just 
mentioned,  the  voids  were  38  per  cent,  in  the  sand,  dry,  and  52  per  cent,  in  the 
same  sand,  moist. 

Because  of  such  discrepancies,  the  author  prefers  to  mix  the  sand  with  the 
cement  and  water,  and  determine  the  voids  in  the  fresh  mortar,  as  described  later. 
This  gives  a  true  comparison  of  different  sands,  since  with  the  same  percentage 
of  cement,  the  mortar  having  the  lowest  air  plus  water  voids  is  the  strongest. 

COARSENESS  OF  SAND. — A  coarse  sand  produces  the  densest,  and,  there- 
fore, the  strongest  mortar  or  concrete.  A  sufficient  quantity  of  fine  grains  is 
valuable  to  grade  down  and  reduce  the  size  of  the  voids,  but  in  ordinary  natural 
material,  either  sand  or  screenings,  there  will  be  found  sufficient  fine  material  for 
ordinary  proportions,  such  as  1:1,  1:2,  or  1:2^2.  For  leaner  proportions,  such  as 
1:4  or  1:5,  and  sometimes  1:3,  an  addition  of  fine  particles  will  be  found  advan- 
tageous to  assist  the  cement  in  filling  the  voids.  A  dirty  sand,  that  is,  one  con- 
taining fine  clay  or  other  mineral  matter,  up  to  say,  10  per  cent.,  is  actually  found 
by  tests  to  be  better  than  a  clean  sand  for  lean  mortars. 

For  water-tight  work  it  is  probable  that  a  larger  proportion  of  very  fine  grains 
may  be  employed  than  for  the  best  results  in  strength.  This  is  a  question,  how- 
ever, which  has  not  yet  been  thoroughly  investigated. 

Feret's  rule  for  sand  to  produce  the  denest  mortar  is  to  proportion  the 
coarse  grains  as  double  the  fine,  including  the  cement,  with  no  grains  of  interme- 
diate size.  There  is  difficulty  in  an  exact  practical  application  of  this  rule,  but  it 
indicates  the  trend  to  be  followed  in  seeking  maximum  density  and  strength. 

CLEANNESS  OF  SAND.— An  excess  of  fine  material  or  dirt,  as  has  just  been 
noted,  weakens  a  mortar  which  is  rich  in  cement.  It  may  also  seriously  retard 
its  setting.  The  author's  attention  was  recently  called  to  a  concrete  lining,  one 
portion  of  which  failed  to  set  hard  for  several  weeks,  although  the  same  cement 
was  used  as  on  adjacent  portions  of  the  work.  The  difficulty  proved  to  be  due 
entirely  to  the  fact  that  the  contractor  substituted,  in  this  place,  a  very  fine  sand, 
the  regular  material  happening  to  run  low. 

SHARPNESS  OF  SAND. — Notice  that  the  quality  of  sharpness  has  not  been 
mentioned  among  the  essential  characteristics  of  sand.  This  omission  was  inten- 
tional. The  majority  of  specifications  still  call  for  "sharp"  sand,  and  yet  the  writer 
has  never  known  a  sand  to  be  rejected  simply  because  of  its  lack  of  sharpness.  As 
a  matter  of  fact,  if  two  sands  have  the  same  sized  grains,  and  contain  an  equal 
amount  of  dust,  the  one  with  rounded  grains  is  apt  to  give  a  denser  and  stronger 
mortar  than  the  sharp  grained  sand.  A  sand  with  a  sharp  "feel"  is  preferable  to 
another,  not  to  any  extent  because  of  its  sharpness,  but  because  the  grittiness  in- 
dicates a  silicious  sand  which  is  apt  to  have  no  excess  of  fine  material. 

41 


SAND  VS.  BROKEN  STONE  SCREENINGS.— Many  comparative  tests 
of  sand  and  screenings  have  been  made  with  contrary  results.  While  frequently 
crusher  screenings  produce  stronger  mortar  than  ordinary  sand,  the  author  in  an 
extensive  series  of  tests  has  found  the  reverse  to  be  true.  This  disagreement  is 
probably  due  to  the  grading  of  the  particles,  although  in  certain  cases  the  screen- 
ings may  add  to  the  strength  because  of  hydraulicity  of  the  dust  when  mixed  witli 
cement. 

TESTING  SAND. 

In  the  previous  paragraphs  are  shown  the  defects  in  the  more  common  methods 
of  examining  sand. 

Tests  made  by  the  author  in  1903  proved  the  value  of  the  principles  of  the 
density  of  mortars  laid  down  by  Feret,  and  in  the  winter  of  that  year  similar  plans 
for  testing  aggregates  were  introduced  by  Mr.  William  B.  Fuller  and  the  author 
at  Jerome  Park  Reservoir,  New  York  City.  The  object  of  the  test  is  to  determine 
which  of  two  or  more  sands  will  produce  the  denser,  and  therefore  the  stronger, 
mortar  in  any  given  proportions. 

The  different  results  in  strength  which  Mr.  Feret  found  with  coarse,  medium 
and  fine  sand  respectively  have  already  been  given,  these  relative  strengths  in 
compression  being  respectively  5,200,  3,400  and  1,900  pounds,  with  proportions 
i  :2'/2  by  weight  in  each  case.  An  examination  of  the  tests  shows  that  the 
strongest  mortar  was  also  densest;  that  is,  the  smallest  volume  or  yield  of  mortar 
was  produced  with  a  given  weight  of  aggregate. 

The  mortar  of  medium  sand  occupied  a  volume  jl/2  per  cent,  in  excess  of  the 
volume  of  the  mortar  with  coarse  sand;  and  the  mortar  of  fine  sand,  a  volume  17 
per  cent,  in  excess  of  the  mortar  with  coarse  sand. 

Following  these  principles,  two  sands  may  be  compared  and  the  better  one 
selected  by  determining  which  produces  the  smallest  volume  of  mortar  with  the 
given  proportions  by  weight.  Using  the  method  described  below,  the  author  has 
been  able  to  increase  the  strength  of  a  mortar  about  40  per  cent,  by  merely  chang- 
ing the  sizes  of  grains  of  the  aggregate. 

The  method  of  making  the  test  is  as  follows:  If  the  proportions  of  the 
cement  to  sand  are  by  volume,  they  must  be  reduced  to  weight  proportions;  for 
example,  if  a  sand  weighs  83  pounds  per  cubic  foot  moist,  and  the  moisture  found 
by  drying  a  small  sample  of  it  at  212°  Fahr.  is  4  per  cent.,  which  corresponds  to 
about  3  pounds  in  the  cubic  foot,  the  weight  of  dry  sand  in  the  cubic  foot  will  be 
83~ 3=8o.  If  the  proportions  by  volume  are  1 :3,  that  is,  one  cubic  foot  dry  cement 
to  3  cubic  feet  of  moist  sand,  and  if  we  assume  the  weight  of  the  cement  as  100 
pounds  per  cubic  foot,  the  proportions  by  weight  will  be  too  pounds  cement  to 
3x80=240  pounds  sand,  which  correspond  to  proportions  i  12.4  by  weight. 


A  convenient  measure  for  the  mortar  is  a  glass  graduate,  aboat  il/2  inches  in 
diameter,  graduated  to  250  cubic  centimeters.  A  convenient  weight  of  cement  plus 
sand,  for  a  test,  is  350  grams.  For  weighing,  the  author  employs  Harvard  Trip 
scales,  which  weigh  with  fair  accuracy  to  one-tenth  of  a  gram.  The  sand  fs  dried 
and  mixed  with  cement,  in  the  calculated  proportions,  in  a  shallow  pan  about  10 
inches  in  diameter  and  I  inch  deep.  The  mixing  is  conveniently  done  with  a  4-inch 
pointing  trowel.  The  dry  mixed  material  is  formed  into  a  circle,  as  in  mixing 
cement  for  briquets,  and  sufficient  water  added  to  make  a  mortar  of  plastic  con- 
sistency, similar  to  that  used  in  laying  brick  masonry.  After  mixing  five  minutes, 
the  mortar  is  introduced  about  20  c.c.  at  a  time  into  the  graduate,  and  to  expel 
any  air  bubbles,  is  lightly  tamped  with  a  round  stick  with  a  flat  end.  The  mortar 
is  allowed  to  settle  in  the  graduate  for  one  or  two  hours  until  the  level  becomes 
constant,  when  the  surplus  water  is  poured  off,  and  the  volume  of  the  mortar  in 
cubic  centimeters  is  read.  For  greater  exactness,  a  correction  may  be  introduced 
for  mortar  remaining  on  pan  and  trowel.  The  other  sands,  which  are  to  be  com- 
pared with  this  one,  are  then  mixed  with  cement  in  the  same  proportions  by  dry 
weight,  and  sufficient  water  added  to  give  the  same  consistency.  The  percentage 
of  water  required  will  vary  with  the  different  aggregates,  the  finer  sand  requiring 
the  more  water.  After  testing  all  the  mortars,  the  sand  which  produces  the 
strongest  mortar  is  immediately  located  as  that  in  the  mortar  of  lowest  volume. 
By  systematic  trials,  the  best  mixture  of  two  or  more  sands  may  also  be  found. 

In  some  cases  a  correction  must  be  introduced  for  the  specific  gravity  of  the 
sand;  for  example,  ordinary  bank  sand  has  an  average  specific  gravity  of  2.65,  but 
if  this  is  to  be  compared  with  broken  stone  screenings  having  a  specific  gravity 
of,  say,  2.80,  the  proportions  of  the  two  must  be  made  slightly  different.  For 
these  particular  specific  gravities,  proportions  1 13,  by  weight,  with  sand,  correspond 
in  absolute  volume  to  proportions  1 :3.2,  by  weight,  of  the  screenings. 

In  making  these  tests,  it  is  also  important  to  notice  the  character  of  the  mor- 
tar as  it  is  being  mixed.  It  should  work  smooth  under  the  trowel  and  be  prac- 
tically free  from  air  bubbles. 

CALCULATING  RELATIVE  STRENGTHS  OF  MORTARS. 

From  the  results  of  the  tests  described,  it  is  possible  to  very  closely  estimate 
the  relative  strength  of  different  mortars  made  with  the  same  cement.  A  formula 
is  given  by  Mr.  Feret*  for  calculating  the  strength  from  the  absolute  volumes  of 
the  ingredients  of  the  mortar,  but,  wishing  to  avoid  the  calculation  of  the  absolute 
volumes  and  obtain  the  result  directly  from  the  weights  of  the  materials  and  the 
volume  of  the  mortar  made  from  them,  the  writer  has  found  it  possible  to  evolve 
from  Feret's  formula  one  which  makes  use  only  of  the  data  from  the  tests  in  the 
graduates  above  described. 


Taylor  &  Thompson'i  "  Concrete,  Plain  and  Reinforced,"  page  139. 
43 


The  formula  is  as  follows: 
Let 

P  =  compressive  strength  of  mortar  in  pounds  per  square  inch. 

K  =  a  constant. 

Q  =:  measured  volume  or  quantity  of  mortar  in  cubic  centimeters. 

C  =  weight  of  cement  used  in  grams. 

S  =  weight  of  sand  used  in  grams. 

Gc   =  specific  gravity  of  cement. 

Gs  =  specific  gravity  of  sand. 
Then 


This  formula  may  be  readily  altered  to  apply  to  the  English  system  of  weights 
and  measures. 

The  value  of  K  varies  with  different  cements  and  different  ages  of  the  same 
mortar,  hence,  it  is  simplest  to  disregard  the  actual  strength,  and  consider  the 
relative  strengths  of  any  two  or  more  mortars  as  in  direct  proportion  to  the  values 
of  the  square  of  the  quantities  in  brackets. 

If  the  aggregates  to  be  compared  have  similar  specific  gravity,  as  in  the  case 
with  different  natural  sands,  the  relative  strengths  of  the  mortars  will  be  in  pro- 
portion to  the  values  of  /  C  \2 


To  illustrate  the  practical  value  of  the  formula,  aside  from  the  theory,  it  may 
be  of  interest  to  refer  to  a  recent  series  of  comparative  tests  made  in  the  author's 
laboratory.  A  mixture  of  sand  and  cement  in  proportions  70  grams  cement  to 
276  grams  sand  produced  in  the  graduate  a  volume  of  mortar  of  178  c.  c.  After 
making  a  number  of  trial  tests,  using  in  every  case  the  same  proportions  by 
weight,  a  new  mixture  of  sizes  of  the  same  aggregate  was  obtained,  whose  volume 
when  mixed  with  the  cement  and  water  was  165  c.  c.  The  specific  gravity  of  the 
sand,  which  in  this  instance  was  crushed  rock,  in  both  cases  was  2.88.  Substitut- 
ing these  values  in  the  formula,  we  find  the  ratio  of  the  two  tests  to  be  i  to  1.40, 
that  is,  the  mortar  having  the  smallest  volume  ought  to  be  1.40  times  (or  40  per 
cent.)  stronger  than  the  other.  Actual  tests  of  the  two  mortars, — afterwards  made 
in  similar  proportions  into  long  prisms, — gave  at  the  end  of  14  days  an  average  of 
832  pounds  per  square  inch  for  one  and  1,153  pounds  per  square  inch  for  the  other, 
thus  showing  an  actual  excess  of  strength  of  39  per  cent.,  which  is  substantially 
identical  with  the  estimated  increase. 

TESTING  CONCRETE  AGGREGATES. 

For  concrete  in  any  given  proportions,  the  best  sizes  of  stone  and  of  sand  may 
be  determined  by  similar  methods  to  those  described  for  testing  sand  mortars, 

44 


although  larger  quantities  of  materials  must  be  used  and  the  measure  must  be 
strong  to  withstand  the  light  ramming  which  is  necessary.  A  short  length  of  cast 
iron  pipe,  closed  at  one  end,  may  be  used  for  this. 

The  aggregates,  which  mixed  with  cement  in  the  required  proportions  pro- 
duce the  smallest  volume  of  concrete,  are  usually  the  best,  although,  as  already 
indicated,  the  shape  of  the  particles  and  their  hardness  must  also  be  taken  into 
consideration. 

PROPORTIONING  CONCRETE. 

A  general  principle  of  practical  use  in  determining  the  relative  proportions  of 
two  or  more  aggregates  in  a  concrete  is  that,  the  weight  of  material  and  the  per- 
centage of  cement  remaining  the  same,  the  mixture  producing  the  smallest  volume 
of  concrete  is  the  best. 


CHAPTER  IV. 


PACIFIC  COAST  BORAX  REFINERY. 

The  distinction  of  being  the  designer  and  builder  of  the  first  two  reinforced 
concrete  factory  buildings  in  the  world  undoubtedly  belongs  to  Mr.  Ernest  L. 
Ransome,  of  the  Ransome  &  Smith  Company.  Of  these  the  Pacific  Coast  Borax 
Refinery  at  Bayonne,  N.  J.,  a  few  miles  from  Jersey  City,  deserves  special  atten- 
tion not  only  as  one  of  the  earliest  examples  of  this  type  of  construction,  but  for 
its  notable  record  in  passing  through  a  terrific  fire  without  structural  injury. 
Moreover,  the  fact  that  it  was  not  erected  until  1897-8  serves  to  emphasize  the 
marvelous  growth  in  reinforced  concrete  construction. 

The  time  is  so  recent  and  reinforced  concrete  buildings  are  now  so  common 
that  it  is  difficult  to  appreciate  the  boldness  of  the  conception  to  construct  a 
4-story  building,  to  sustain  actual  working  loads  of  400  pounds  per  square  foot 
besides  heavy  machinery  even  on  the  top  floor,  out  of  a  material  until  recently 
used  almost  exclusively  for  foundations,  and  considered  capable  of  resisting  only 
compressive  loads.  Of  course,  the  principle  of  steel  reinforcement  in  concrete  had 
been  understood  for  a  number  of  years  previous  to  1897.  In  fact,  a  house  of  rein- 
forced concrete  was  built  in  Port  Chester,  N.  Y.,  as  early  as  1871,  and  a  few  other 
similar  structures  appeared  between  this  date  and  1897.  But  with  the  exception 
of  the  factory  at  Alameda,  Cal.,*  also  designed  and  built  by  Mr.  Ransome,  the 
Pacific  Coast  Borax  Building  appears  to  be,  as  above  intimated,  the  first  attempt 
at  concrete  factory  construction. 

While  it  is  not  claimed  that  the  design  of  this  factory  is  in  all  respects  typical 
of  the  up-to-date  concrete  factory  building  as  now  erected  by  the  Ransome  & 
Smith  Company  and  other  contractors,  many  of  its  features  and  the  methods  em- 
ployed in  its  construction  are  well  worth  consideration. 

As  built  to-day,  double  walls  are  not  regarded  as  essential  for  factories,  but 
instead  the  wall  surface  is  usually  taken  entirely  by  windows  separated  by  con- 
crete columns  which  support  the  floors  above.  In  the  floor  system,  slabs  of 
longer  span  with  correspondingly  heavier  beams  are  now  more  common,  while 
expansion  joints  in  floors  are  not  usually  specified  unless  the  building  covers  an 
extremely  large  area. 

DESIGN. 

The  main  building  is  200  feet  long  by  75  feet  wide,  and  four  stories  high, 
rising  70  feet  above  the  ground.  Connected  with  this  and  forming  a  part  of  it  is 
a  section  which  was  built  first  only  one  story  high,  and  then  after  the  fire  carried 


Illustrated  on  page  210. 


up  to  the  full  four  stories,  as  shown  in  Fig.  i.    The  area  of  ground  covered  by  the 
combined  buildings  is  50,000  square  feet. 

The  plan  of  the  first  story  is  shown  in  Fig.  2,  the  junction  between  the  four- 
story  and  the  one-story  portion  being  indicated  by  the  dot  and  dash  line  AA.  In 
order  to  show  the  plan  on  a  large  scale,  the  first  floor  of  the  four-story  building 
is  drawn  in  full  and  a  part  of  the  one-story  portion  is  omitted  as  indicated  by  the 
irregular  lines  BB. 

The  bays  in  general  are  24  ft.  &%  inches  x  12  ft.  4^5  inches;  the  columns  in 
the  first  story  are  21  inches  square,  in  the  second  story  19  inches,  in  the  third 
story  17  inches,  and  in  the  fourth  story  12  inches.  They  are  computed  by  a  max- 
imum compression  of  500  pounds  per  square  inch. 

The  sectional  elevation  in  Fig.  3  shows  the  columns  and  also  the  column  foot- 
ings which  are  reinforced  in  the  bottom  with  horizontal  rods.  The  footings  were 
designed  so  that  the  compression  upon  the  soil,  which  is  of  a  marshy  character, 
should  not  exceed  2,500  pounds  per  square  foot. 

Fig.  3  also  illustrates  the  construction  of  the  floor  system,  and,  taken  in 
connection  with  a  plan  of  a  portion  of  the  second  floor  in  Fig.  2,  gives  a  good 
idea  of  the  type  of  design.  Girders  connect  the  columns  which  are  12  ft.  4^5 
inches  on  centers.  Between  the  girders  and  at  right  angles  to  them,  run  the  con- 
crete floor  beams  about  3  feet  apart  and  so  thin  and  deep  that  they  resemble 
timber  joists  in  appearance.  As  these  beams  are  nearly  25  feet  long  in  the  clear, 
a  stiffening  web  crosses  them  in  the  middle  designed  to  serve  the  same  purpose 
as  bridging  in  wooden  floor  joist  construction,  that  is,  to  assist  in  preventing 
tendency  to  buckle  under  heavy  loads.  The  girders  are  of  rather  peculiar  con- 
struction, being  made  thicker  in  the  panels  next  to  the  columns  so  as  to  save  ex- 
pense in  forms.  (See  Fig.  2). 

Originally,  the  columns  in  the  fourth  story  of  the  main  building  and  also  the 
roof  were  of  wood,  while  the  one-story  part  was  of  similar  construction.  After 
the  fire  the  wood  was  all  replaced  by  concrete,  as  shown  in  the  plans.  The  roofs 
were  then  built  as  reinforced  slabs  of  12  ft.  4^  inches  span  from  centre  to  centre 
of  the  beams,  the  latter  being  24  ft.  8%  inches  long  between  column  centres.  Still 
later  the  roof  of  the  low  part  formed  the  floor  for  the  second  story  when  this 
portion  of  the  building  was  raised  to  full  height,  as  shown  in  the  finished  photo- 
graph, Fig.  I. 

The  reinforcement  of  the  beams  and  girders  and  stiffeners  of  the  principal 
floors  is  shown  at  the  lower  part  of  the  diagram,  Fig.  3.  The  slabs  were  built  of 
such  short  span  that  they  received  no  reinforcement,  the  depth  being  4  inches  in 
addition  to  the  l-inch  cement  finish. 

The  floors  with  the  beams  and  girders  were  laid  as  separate  panels  about  24 
feet  square,  a  vertical  contraction  joint  being  carried  down  through  the  beams 
on  a  line  with  alternate  columns;  that  is,  every  eighth  beam  was  built  double.  As 

48 


fwn  of  Tmeafnoor  cans  true ff on 


Fig.  2.— Plan  of  First  Story  of  Pacific  Coast  Borax  Refinery.      (See  p.  48.) 
49 


stated  above,  it  is  not  now  customary  to  insert  contraction  joints  except  on  ex- 
traordinarily large  surfaces,  the  contraction  being  provided  for  instead  by  the  steel 
reinforcement  in  the  beams  and  slabs. 

Details  of  the  hollow  wall  construction   are  presented   in   Fig.  4.     The  total 
thickness  of  all  the  walls  is   16  inches  for  the  entire  height  of  the  building,  the 


^  1 

^ 

^ 

^ 

Ovte/afe,  of  W&//. 

CVJ 

M 

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(VJ 

i  r^ 

' 

^ 

]c~ 

}  (i 

^ 

^) 

^ 

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( 

- 

i 

^ 

^ 

Fig.    4.— Typical    Horizontal    Section    of    Wall.      (See  p.  51.) 


outer  surface  being  only  2  inches  thick,  and  the  inner  surface  varying  from  4  inches 
in  the  first  story  to  \1A  inches  in  the  fourth  story.  The  length  of  the  hollow 
spaces  in  the  walls  is  variable,  depending  upon  the  number  and  location  of  the 
windows.  The  webs  connecting  the  two  walls  are  3  1/16  inches  thick  on  the 
north  and  south  sides  of  the  building  and  4^2  inches  thick  on  -the  east  and  west. 
This  hollow  construction  has  proved  satisfactory  and  given  a  good  roomy  build- 
ing with  no  condensation  on  the  inner  walls ;  but,  as.  previously  stated,  it  is  not 
now  considered  necessary  in  factory  construction  to  incur  the  expense  of  coring 
out  the  walls,  and  it  is  more  usual  to  build  them  solid. 

The  exterior  walls  were  finished  by  picking  the  surface  with  a  sharp  tool  which 
removed  the  outside  skin  of  cement  so  as  to  show  the  stone  and  mortar  between 
and  resemble  pean  hammered  masonry.  A  part  of  this  work  was  done  by  hand 
and  part  with  pneumatic  hammers.  Although  a  pneumatic  hammer  averaged 
about  400  square  feet  in  ten  hours,  while  by  hand  100  to  150  square  feet  was  a  fair 
day's  work  for  a  man,  the  actual  cost  with  the  power  tool  was  but  slightly  less 
than  by  hand  because  of  the  higher  grade  of  men  required,  the  extra  men  for 
shifting  air  pipes,  etc.,  and  the  wear  and  tear  on  the  tools. 

51 


Fig.   5.— Molding   for   Wall   Joints.*      (See  p.   52.) 

The  surface  was  also  divided  into  blocks  by  wood  moldings  nailed  to  the  in- 
side of  the  fflrm.     A  section  of  the  molding  is  shown  in  Fig.  5. 

The  stairs  are  also  of  reinforced  concrete,  typical  details  being  given  in  Fig.  6. 


'////////////) 


&"£buaJAjbds 

^?e.cf/o/?"AA" 


A-6* 


No.  6. — Sketches  of  Stair  Construction.      (See  p.  52.) 


In  Fig.  7  is  shown  the  150  foot  concrete  chimney  which  is  located  in  the 
middle  of  the  building.  (See  Fig.  2).  It  was  built  with  two  independent  shells 
of  concrete. 

PROPORTIONS  OF  THE  CONCRETE. 

The  proportions  of  cement  to  aggregate  in  the  concrete  varied  in  different 
parts  of  the  work.  For  the  aggregate,  broken  basaltic  rock  brought  down  from 
the  Palisades  of  the  Hudson  was  chiefly  used.  The  size  was  limited  to  particles 


*  Reproduced  by  permission  from  Taylor 


Thompson's   "Concrete,    Plain   and   Reinforced," 
52 


JOB* 


\ 


'yteffT? 


Warn 


T*- 


^ 


- 


Concrete 


Fig.  7.— Plan   and  Elevation   of  Chimney.       (See  p.   52-) 
53 


passing  a  2-inch  ring,  while  for  much  of  the  work  that  which  passed  a  i-inch  ring 
was  employed.  The  dust  was  left  in  the  rock  and  provided  so  much  fine  ma- 
terial that  only  a  small  quantity  of  sand,  averaging  not  more  than  10  per  cent., 
was  needed. 

The  proportions  of  the  footings  were  i  part  Atlas  Portland  cement  to  10  parts 
of  this  aggregate.  The  columns  were  of  i  :$  mixture,  and  the  walls,  floors  and 
stairs  of  1 :6Y2. 

For  imbedding  the  rods  in  the  bottom  of  the  floor  beams  a  i  :6  mix  was  em- 
ployed, using  very  fine  stone  for  the  concrete. 

Concrete  of  i  :6l/2  proportions  made  into  3-inch  cubes  gave  a  compressive 
strength  of  900  pounds  per  square  inch  at  the  age  of  7  days. 

CONSTRUCTION. 

Construction  was  begun  late  in  the  fall  of  1897  and  completed  in  October 
1898.  The  usual  time  per  story  was  40  to  50  days,  whereas  now  such  a  building 
would  be  put  up  by  the  same  builders  at  the  rate  of  a  story  in  one  or  two  weeks. 

The  materials  for  the  concrete  included  10,000  barrels  of  cement  and  nearly  as 
many  cubic  yards  broken  stone,  the  stone  being  brought  in  scows  down  the  Hud- 
son River  and  piled  near  the  shed,  in  which  1,000  bags  of  cement  were  stored. 


Fig.    8. — Type    of    Wall    Molds.      (See  p.  55.) 


The  construction   plant    was   of  quite    elaborate    design.     The   cement    having 
been   wheeled   from   the   shed   and   the   stone   measured   in   barrows,   both    materials 

54 


were  dumped  into  a  hopper  which  discharged  into  a  car.  This  car  was  hauled 
by  cable  through  a  subway  and  then  up  an  incline  to  about  30  feet  above  the 
hopper  and  about  400  feet  distant,  where  it  was  automatically  tipped  into  a  chute 
leading  to  the  mixer.  The  mixer,  of  substantially  the  same  type  as  the  Ransome 
machines  now  in  general  use,  discharged  into  a  trough  containing  a  screw  con- 
veyor which  delivered  the  wet  concrete  to  a  vertical  bucket  elevator  and  this 
hoisted  the  material  to  the  story  where  it  was  required,  and  dumped  it  upon  a 
platform  which  held  about  one  cubic  yard. 

A  steam  engine  operated  the  car,  mixer  and  elevator,  and  also  ran  a  twist- 
ing machine,  bolt  cutter  and  two  or  three  other  tools.  The  column  forms  were 
built  in  the  usual  way  with  vertical  boards  paneled  together,  and  held  with  clamps 
surrounding  them.  The  wall  forms  were  y%  inch  dressed  boards,  designed  in  gen- 
eral like  Fig.  8. 

These  forms,  patented  by  Mr.  Ransome  in  1885,  are  still  extensively  used  in 
wall  construction.  The  special  feature  is  the  vertical  standard  made  of  two  i  by 
6  inch  boards  on  edge  with  a  slot  between,  through  which  passes  the  bolts.  By 
loosening  the  nut,  the  plank  behind  the  standards  may  be  loosened  and  the  stand- 
ards raised.  The  walls  were  built  in  sections  4  feet  high  with  central  cores  to 
form  the  hollow  walls. 

White  pine  was  used  for  forms,  and  the  salvage  on  the  lumber  probably  did 
not  amount  to  more  than  10  per  cent.,  although  by  present  methods  the  builders 
usually  figure  about  30  per  cent. 

The  total  cost  of  the  building  was  in  the  neighborhood  of  $100,000. 

THE  FIRE. 

Some  four  years  after  completion,  in  the  spring  of  1902,  the  Refinery  was 
subjected  to  one  of  the  most  severe  fires  to  which  a  manufacturing  building  is 
liable.  Although  the  building  itself  is  of  concrete,  it  contained  a  large  amount  of 
wood  in  the  form  of  partitions,  window  frames  and  bins,  in  addition  to  the  wooden 
roof,  and  at  the  time  of  the  fire  one  room  happened  to  be  completely  filled  with 
empty  wooden  casks  which  provided  yet  more  fuel  for  the  flames.  Some  of  the 
material  used  in  the  manufacturing  process  was  also  extremely  inflammable. 

To  illustrate  the  heat  of  the  fire,  an  insurance  man  called  attention  to  the  fact 
that  the  plank  roof  was  entirely  gone,  with  no  charred  wood  remaining,  the  brass 
in  the  dynamos  was  melted,  and  at  least  in  one  case  a  piece  of  cast  iron  was 
fused  into  a  misshapen  mass.  A  photograph  of  the  melted  cast  iron  is  shown  in 
Fig.  9. 

This  fusing  of  the  iron  is  especially  remarkable  since  cast  iron  melts  at  the 
high  temperature  of  about  2200°  Fahr.  The  piece  appears  to  be  a  portion  of  a 
pulley  which  was  probably  located  near  an  opening  in  the  floor  through  which 
there  was  a  tremendous  draft  of  flame. 

55 


Fig.  9. — Photograph  of  Cast  Iron   Melted  by  the   Fire.      (See  p.  55.) 


The  chief  structural  damage  to  the  building  at  the  time  of  the  fire  was  caused 
by  the  fall  of  an  iron  tank  which  was  located  on  the  wooden  roof  and  supported 
by  timbers  from  the  fourth  floor.  This  weight  coming  suddenly  upon  the  floor 
broke  the  slab  and  two  or  three  of  the  floor  beams,  but  did  not  pass  through  to 
the  floor  below,  being  caught  by  the  damaged  floor. 

In  several  places  throughout  the  building  the  concrete  had  been  split  off  by 
the  fire  to  a  depth  of  %  to  one  inch,  and  on  one  of  the  exterior  walls  a  few  cracks 
showed  over  a  doorway.  The  total  cost  of  repairs,  including  the  portion  of  the 
floor  broken  by  the  tank,  was  in  the  neighborhood  of  $r,ooo.  The  broken  beams 
were  repaired  by  inserting  new  concrete  in  the  central  portion  and  supporting  it 
by  bolts  run  down  through  the  ends  of  the  beams  which  still  remained  in  place. 

As  a  result  of  the  fire  the  structure  was  completely  gutted,  nothing  remaining 
but  the  reinforced  concrete  and  a  mass  of  charred  wood,  with  the  machinery, 
shafting,  dynamos,  etc.,  melted  or  twisted  out  of  shape.  A  photograph  taken 
directly  after  the  disaster  before  any  repairs  were  made  is  given  in  Fig.  10.  This 
photograph  also  presents  a  very  good  view  of  the  Refinery  itself  with  the  main 
building  and  the  one-story  addition. 

In  contrast  with  the  durability  of  the  reinforced  concrete  under  the  action  of 


57 


Fig.   11.— Effect  of  Fire  Upon   Steel  Tank   House.      (See  p.  58.) 

the  fire  is  a  steel  tank  house  adjoining  the  building.  This  was  built  with  steel 
columns  and  roof  girders,  and  the  effect  of  the  heat  upon  the  steel  structure  is 
graphically  shown  in  Fig.  n. 

A  photograph  of  the  Refinery,  taken  in  1907  and  shown  as  Fig.  i  on  page  46, 
presents  one  view  of  the  buildings,  and  in  Fig.  12  is  another  1907  view,  showing 
in  the  foreground  the  new  part  also  built  by  Ransome  &  Smith  and  the  older 
structure  in  the  background. 


.18 


No.    14.— The  Ketterlinus    Building.      (See  p.  61.) 
60 


CHAPTER  V. 


KETTERLINUS  BUILDING. 

The  plant  of  the  Ketterlinus  Lithographic  Manufacturing  Company  is  located 
in  Philadelphia  at  the  northwest  corner  of  Fourth  and  Arch  streets,  and  the  rein- 
forced concrete  portion  of  the  structure  built  in  1906  represents  a  type  of  building 
adapted  to  city  manufacturing  establishments  limited  to  a  comparatively  small 
ground  area.  The  building  illustrated  on  the  opposite  page  as  Fig.  14  is  eight 
stories  high  besides  the  basement,  and  its  dimensions  are  80  by  67  feet.  The 
architects  and  engineers  were  Ballinger  &  Perrot,  of  Philadelphia,  and  they  also 
supervised  the  erection,  which  was  done  by  day  labor  with  no  general  contractor. 

This  new  building  adjoins  and  forms  a  part  of  the  old  plant  of  the  Ketterlinus 
Company,  which  is  of  steel  frame  construction,  fireproofed  with  terra  cotta. 

In  both  buildings  heavy  machinery  is  now  running,  and  many  large  printing 
presses  are  at  work  on  the  third,  fourth  and  fifth  floors.  Because  of  the  proximity 
of  the  old  and  new  types  of  construction  the  advantages  of  the  reinforced  concrete 
from  the  point  of  view  of  the  manufacturer  are  particularly  evident.  In  the  build- 
ing of  steel  and  terra  cotta  construction  the  vibration  from  the  machinery  is 
noticeable  as  soon  as  one  enters,  while,  on  the  other  hand,  in  the  new  structure 
the  concrete  because  of  its  greater  mass  and  inertia,  absorbs  the  vibrations,  and 
it  is  difficult  to  appreciate  the  speed  and  power  of  the  machines.  As  a  result, 
too,  of  this  reduction  in  the  vibration  the  noise  of  the  machinery  is  effectually 
deadened. 

The  building  is  designed  for  a  working  load  of  400  pounds  per  square  foot. 
The  concrete  for  practically  the  whole  of  the  work  was  proportioned  i  :2j^  15, 
equivalent  by  actual  measurement  to  one  barrel  (4  bags)  Atlas  Portland  cement 
to  gl/2  cubic  feet  of  sand  to  19  cubic  feet  broken  stone,  the  basis  of  proportioning 
is  in  a  barrel  of  3.8  cubic  feet.  The  sand  was  well  graded  coarse  material,  fre- 
quently termed  in  the  region  of  Philadelphia  "Jersey  gravel" ;  the  stone  was  trap 
rock  broken  to  a  size  at  which  all  the  particles  would  pass  a  one-inch  ring  ex- 
cepting the  stone  in  the  concrete  immediately  surrounding  the  steel,  which  was 
of  a  size  to  pass  through  a  half-inch  ring. 

-  To  harmonize  with  the  old  adjoining  building  of  which  it  forms  a  part,  the 
exterior  walls  are  faced  with  brick  with  terra  cotta  trimmings. 

DESIGN. 

Several  features  in  the  design  of  the  Ketterlinus  building  are  of  unusual  in- 
terest. The  columns  below  the  fifth  floor,  instead  of  the  usual  solid  concrete  con- 

61 


struction  with  four  or  more  round  rods  for  reinforcement,  are  essentially  steel 
columns  surrounded  by  concrete.  The  beams  and  girders  are  reinforced  with  the 
unit  frame  system  in  which  the  steel  is  all  put  together  in  the  shop  and  brought 
to  the  job  ready  to  place  in  the  form.  The  sawtooth  roof  is  also  a  novel  feature 
for  reinforced  concrete. 

The  columns  are  spaced  13  feet  6  inches  apart  in  one  direction  and  19  feet 
2  inches  in  the  other.  The  girders  follow  the  shorter  span,  and  the  bays  are 
divided  into  three  panels  by  the  cross  beams,  as  shown  in  Fig.  15.  The  vertical 
section,  Fig.  16,  also  illustrates  the  arrangement  of  the  columns  and  beams,  the 
window  lintels  and  the  sections  of  brick  wall  below  the  windows. 


Pit-    15.— Typical   Floor  and   Roof   Plans  of  the   Ketterllnus   BuildinE. 

69 


Fig.    16. — Cross-Section    of 


Ketterlinus    Building.       (Se 
63 


COLUMNS. 

One  of  the  problems  in  concrete  building  construction  where  the  loads  are 
heavy  or  the  building  is  several  stories  high  is  to  build  the  columns  small  enough 
to  satisfy  the  requirements  of  the  occupants  and  owners  without  overloading  the 
concrete.  Its  solution  is  especially  difficult  in  a  city  building  where  the  land  area 
is  so  valuable  that  every  square  inch  of  floor  space  is  at  a  premium,  and  where 


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Flg.   17. — Details  of  Columns  and  Girders.      (See  p.  65-) 
64 


there  must  be  more  stories  than  are  economical  under  other  conditions.  More- 
over, the  building  laws  of  many  cities  require  more  conservative  loading  than 
might  be  warranted  if  it  were  certain  that  the  conditions  of  construction  were  in 
all  cases  the  best. 

In  a  number  of  recent  instances  the  difficulty  has  been  met  by  the  use  of 
composite  columns,  a  combination  of  concrete  and  structural  steel,  and  this  is  the 
plan  followed  by  the  designers  of  the  Ketterlinus  building.  Full  details  of  the 
column  construction  are  presented  in  Fig.  17. 

The  interior  columns  in  the  building  up  to  the  fifth  floor  are  23  inches  in 
diameter.  In  the  basement  and  the  four  lower  stories,  the  core  of  the  column  is 
formed  of  steel  plates  and  angle  irons  riveted  together  in  the  form  of  a  cross. 
Around  this  cross  l/%  inch  wire  ties  were  placed  every  12  inches  and  looped 
around  four  vertical  round  rods  which  increased  the  reinforcement.  In  the  base- 
ment, for  example,  the  centre  steel  is  made  up  of  a  plate  18  inches  wide  and  fy& 
inch  thick  with  two  plates  of  similar  thickness  but  8  inches  wide  at  right  angles  to 
it,  and  four  angle  irons  6  by  6  by  ^  inch  all  riveted  together.  The  four  round  rods, 
which  complete  the  so-called  "Star"  reinforcement  are  i%  inch  diameter. 

The  columns  in  the  three  stories  nearest  the  top  are  designed  to  carry  the 
full  dead  and  live  loads  of  floors  and  roof.  In  each  lower  story  the  columns  are 
designed  to  carry  the  full  dead  load  and  a  smaller  proportion  of  the  full  live  load 
than  can  be  carried  by  the  floor  construction,  this  live  load  factor  being  reduced 
proportionately  to  the  number  of  floors  carried ;  for  example,  the  basement  col- 
umns were  calculated  on  a  basis  of  carrying  on  the  steel  cores  alone  three-fourths 
the  live  load  plus  the  full  'dead  load  with  a  factor  of  safety  of  4. 

The  steel  is  designed  to  bear  the  computed  load  without  exceeding  a  maximum 
compression  of  16,000  pounds  per  square  inch.  The  compressive  strength  of  the 
concrete  in  these  columns  is  not  considered,  though  almost  sufficient  to  carry  the 
dead  load. 

The  weight  of  the  girders  is  borne  in  part  by  brackets  of  steel  riveted  to  the 
angle  irons  and  partly  by  the  concrete  knees  or  enlargements  of  the  column  which 
run  out  obliquely  from  the  columns  and  which  are  reinforced  on  each  side  by  two 
^2-inch  rods. 

Above  the  fourth  story  the  columns  are  of  the  same  diameter  but  with  the 
more  ordinary  reinforcement  of  four  round  rods. 

COLUMN  FOOTINGS. 

To  transmit  the  compressive  load  from  the  steel  in  the  columns  to  the  soil,  a 
special  design  of  footing  was  prepared.  A  large  base  was  necessary  to  prevent 
too  great  loading  of  the  soil  beneath  the  building,-  and  in  order  that  the  pressure 
from  the  column  might  not  break  or  crush  the  concrete  over  this  large  area  a 
grillage  of  steel  I-beams  was  placed  under  each  column  (See  Fig.  17),  and  the 

83 


concrete  below  these  I-beams  further  strengthened  against  breakage  and  shear  by 
i -inch  horizontal  round  rods  placed  6  inches  apart,  and  %  by  i-inch  stirrups. 

FLOOR  SYSTEM. 

Each  girder  was  designed  as  an  independent  beam  supported  at  the  ends  by 
the  enlargement  of  the  columns  and  the  steel  brackets.  The  area  of  the  rein- 
forcing steel  was  calculated  in  the  usual  way,  but  instead  of  placing  each  rod 
separately  in  the  form,  girder  frames  were  made  from  quadruple  or  twin  webbed 
bars,  which  were  cut,  bent  to  shape  and  stirrups  fastened  thereto  in  the  shop. 
The  girder  frame  reinforcement  was  brought  to  the  building  in  the  form  of  a 
truss,  and  the  work  of  placing  consisted  simply  of  setting  this  truss  in  the  form 
upon  cast  steel  sockets,  each  having  a  M-inch  threaded  stud  projecting  upward 
through  the  frame.  A  nut  screwed  down  on  this  stud  over  the  frame  holds  it 
rigidly  in  position.  Every  rod  and  every  member  could  not  help  but  be  in 
exactly  the  right  location  in  the  beam.  This  girder  frame  and  socket  were  the 
invention  of  Emile  G.  Perrot,  one  of  the  firm  of  architects  who  designed  the 
building,  the  object  being  to  insure  the  exact  amount  and  arrangement  of  tension 
and  shear  members  in  the  exact  location  as  designed,  and  to  afford  opportunity  for 
inspection  of  the  steel  in  position  before  the  pouring  of  the  concrete. 

In  the  various  plans  the  letter  "Q"  is  entered  as  a  part  of  the  description  of 
the  reinforcement.  This  stands  for  the  word  "Quadruple"  and  indicates  a  group 
of  four  rods  held  at  intervals  by  special  sockets. 

The  rods  are  rolled  in  sets  of  four  connected  by  a  web,  and  this  web  is  sheared 
and  bent  down  in  2-inch  lengths  at  intervals  of  3  inches  to  give  greater  grip  in  the 
concrete.  These  2-inch  lengths  are  bent  back  over  stirrups,  where  they  occur,  to 
clinch  them  in  position  on  the  frame.  The  outside  bars  are  also  cut  loose  at  each 
end  and  bent  upwards  to  reinforce  the  top  of  the  beam  near  the  supports.  The 
sockets  (Fig.  17)  are  shaped  so  that  they  support  the  rods  il/2  inches  above  the 
bottom  of  the  beam  or  girder,  and  are  held  in  place  by  a  24-inch  bolt  passing 
up  through  the  bottom  of  the  wood  mold.  These  threaded  sockets  afterwards  are 
used  for  securing  shafting,  hangers  or  other  fixtures. 

In  the  various  dimensions  of  beams  on  the  plan  the  width  and  depth  is  given 
first,  followed  by  "i  Q"  or  "2  Q"  (the  latter  meaning  8  rods),  then  the  diameter 
of  rod,  and  finally  the  thickness  of  the  web  forming  a  part  of  the  rods.  Thus 
io"xi8"-2Q^"x^"  means  that  the  beam  is  10  inches  wide  by  18  inches  deep, 
reinforced  with  two  groups  of  four  rods  ^  inch  diameter,  connected  longitudinally 
by  webs  %  inch  thick.  The  depth  of  the  beams  and  girders  is  given  from  the 
under  side  of  the  slab  instead  of  from  the  top  of  the  slab,  the  more  usual  form. 
The  area  of  cross-section  of  each  of  such  "Q"  bars  is  about  3  square  inches. 

The  dabs  are  of  usual  construction,  being  4  inches  thick  and  reinforced  for 
the  net  span  of  3  feet  10  inches  with  3-inch  No.  10  expanded  metal,  this  mesh 

66 


having  been  substituted  instead  of  J^-inch  rods  spaced  6  inches  apart  and  occa- 
sional J4~inch  rods  running  in  the  other  direction,  as  originally  shown  on  the 
drawings,  at  an  increase  of  about  one  per  cent,  of  the  cost  of  the  building. 

The  wearing  surface  is  a  i^-inch  maple  wood  floor  on  2  by  4  inch  sleepers 
16  inches  apart.  The  sleepers  are  placed  on  the  concrete  slab  and  cinder  concrete 
in  proportions  i  :3  7  filled  in  between  them. 

STAIRS. 

The  stairs  are  carried  up  in  brick  towers,  as  required  at  date  of  construction 
by  the  Philadelphia  building  laws.  The  details  of  the  design  and  reinforcement  are 
illustrated  in  Fig.  18. 


3^ 


Fig.    18.  —  Stairs   in   Ketterlinus   Building.      (See  p.  67.) 
67 


The  treads  are  formed  by  i  inch  thickness  of  i  to  i  mortar  or  granolithic 
finish,  and  the  reinforcement  consists  of  J^-inch  rods  placed  6  inches  apart. 

WALLS. 

The  walls  are  essentially  reinforced  concrete  columns,  veneered  on  the  out- 
side with  4  inches  of  brickwork  and  separating  the  windows.  The  window  lintels 
are  of  concrete  faced  with  terra  cotta  to  match  the  red  sandstone  of  the  older 
building  adjoining  and  anchored  to  the  concrete.  The  lintels  form  reinforced 
concrete  beams  and  support  a  brick  wall  13  inches  thick,  which  is  run  up  to  the 
bottom  of  the  terra  cotta  window  sills. 

The  method  of  connecting  the  brick  with  the  concrete  of  the  columns  is  shown 
in  Fig.  19,  copper  wall  ties  1/16  by  24  by  7  inches  being  set  in  the  concrete  at 
intervals,  and,  after  the  removal  of  the  forms,  bent  out  and  laid  into  the  joint  of 
the  face  brick,  which  is  separated  from  the  concrete  by  a  24-inch  mortar  joint 
for  purposes  of  alignment. 


Fig.    19. — Brick   Wall   Ties.      (.SV«/.  68.) 


ROOF. 

The  general  design  of  the  saw-toothed  roof  appears  on  the  full  cross-section, 
Fig.  16  (p.  63).  In  Fig.  20  the  details  are  illustrated.  Inclined  girders  extend 
across  the  building,  and  above  these  project  the  saw  teeth,  which  rest  upon  concrete 
beams  running  into  the  girders.  Saw-tooth  construction  in  reinforced  concrete  is,  of 
course,  expensive,  because  of  the  irregularities  of  the  forms,  but  with  the  aid  of 
the  unit  reinforcing  system,  which  accurately  locates  the  steel,  the  design  is  satis- 
factorily worked  out. 

As  in  the  other  plans,  the  letter  Q  indicates  a  quadruple  bar  whose  web  thick- 
ness is  designated  by  the  final  fraction  in  the  dimensions.  In  the  roof,  instead 
of  the  four  bars  being  on  one  plane  and  rolled  all  together  with  a  single  web,  they 
are  arranged  in  pairs  with  a  web  connecting  the  two  bars  of  each  pair. 


Cross  ^Section  Thro i/ ah 

pening  'for 


Fig.   20. — Cross=Section   Detail   of   Saw-Tooth    Roof.      (See  p.  68.) 

CONSTRUCTION. 

The  concrete  was  mixed  in  the  basement  by  a  Smith  machine,  dumped  from 
the  mixer  into  wheelbarrows  and  raised  on  a  platform  elevator  located  in  the  stair 
tower  to  the  floor  in  process  of  construction,  when  it  was  wheeled  in  the  same 
barrows  and  dumped  directly  into  the  columns  or  floor. 

A  boom  derrick  was  employed  to  handle  the  steel  columns,  lumber  and  brick. 
This  derrick  was  also  used  for  demolishing  and  excavating  before  the  concrete 
was  started. 

A  photograph  of  one  of  the  floors  ready  for  the  concrete  is  shown  in  Fig.  21. 
The  wood  forms  for  the  beams,  girders  and  slabs  are  in  place,  and  the  steel  of  the 
columns  is  set  and  temporarily  braced  with  plank.  In  different  places  on  the 
floor  the  unit  girder  frames  are  seen,  some  of  them  in  place  in  the  mold  and  some 
lying  on  the  floor  ready  to  be  carried  and  lowered  to  position. 

Fig.  22  shows  the  exterior  of  the  building  in  a  later  stage  of  the  construc- 
tion. The  column  forms  have  not  yet  been  removed  from  some  of  the  columns, 
and  many  of  the  braces  are  still  in  place.  The  framework  of  the  platform  elevator 
projects  above  the  structure  at  the  left  of  the  photograph,  while  the  boom  derrick 
is  seen  to  be  located  on  the  roof  of  the  old  part  of  the  building. 

The  progress  per  story  varied  from  eleven  days  to  three  weeks.  The  forms 
were  left  in  place  two  weeks  or  more  and  were  used  three  times,  the  approximate 
salvage  on  the  lumber  for  the  next  job  being  25  per  cent. 

The  interior  of  the  building  is  photographed  in  Fig.  23  (p.  72),  and  shows  one 
of  the  20-ton  lithographic  presses. 

69 


Fig.   22. — Exterior  of   the   Ketterlinus    Building   During   Construction.      (See   p.   69.) 

71     . 


72 


COST. 

The  concrete  portion  of  the  building  cost  $27,000.  This  sum  included  the 
form  work  and  steel  reinforcement,  except  the  column  cores  and  grillage  beams, 
which  cost  $5,500  additional.  The  total  cost  of  the  structure,  including-  the  inside 
finish,  amounted  to  nearly  $90,000. 

The  unit  girder  construction  is  somewhat  more  expensive  than  the  ordinary 
system  of  bending  and  placing  separate  rods,  but  the  result  is  a  sure  location  for 
every  member  with  no  danger  of  a  rod  being  left  out  or  placed  so  high  as  to 
lose  a  large  part  of  its  efficiency.  In  this  particular  building  the  cost  of  the  unit 
girder  reinforcement  was  4  cents  per  pound  after  bending  ready  to  place. 

INSURANCE. 

It  is  of  interest  to  observe  that  the  building  is  insured  by  the  Associated 
Factory  Mutual  Insurance  Companies,  and  at  the  time  of  completion  was  the  only 
building  in  the  congested  portion  of  Philadelphia  which  was  insured  by  them. 

As  a  protection  against  fires  in  neighboring  structures,  the  building  is  fitted 
with  wire  glass  windows  with  metal  frames,  except  in  the  first  story,  which  has 
plate  glass  windows  with  metal  frames.  Openings  in  the  division  wall  between 
the  old  and  new  parts  of  the  plant  are  closed  with  automatic  fire  doors  on  both 
sides  of  the  fire  wall.  Furthermore,  the  building  is  equipped  with  automatic 
sprinklers  supplied  by  a  tank  located  20  feet  above  the  roof.  The  sprinklers  are 
also  connected  with  a  75o-gallon  Underwriters'  fire  pump  supplied  by  two  inde- 
pendent 6-inch  connections  from  the  distribution  system  of  the  city  waterworks, 
and  the  tank  above  the  roof  and  standpipes  in  the  building  are  also  supplied  from 
this  pump.  In  addition  to  this  private  fire  system,  a  standpipe  extending  to  a 
nozzle  monitor  on  the  roof  is  also  provided,  which  is  connected  with  the  Under- 
writers' pump  and  also  with  the  high-pressure  city  mains  by  means  of  hose. 


73 


Fig.   24.— Lynn   Storage   Warehouse.      (See  p.  75.) 
74 


CHAPTER  VI. 


LYNN  STORAGE  WAREHOUSE. 

The  Lynn  Storage  Warehouse,  at  Lynn,  Mass.,  is  built  for  the  storage  of 
general  merchandise  and  furniture,  reinforced  concrete  having  been  selected  as  the 
most  economical  fireproof  construction.  To  provide  for  the  variable  character  of 
its  contents,  the  several  floors  are  designed  to  sustain  different  loading;  the  three 
lower  floors  are  each  planned  for  the  rather  heavy  loading  of  250  pounds  per 
square  foot,  while  on  the  fourth  floor  200  pounds  per  square  foot  of  loading  is  to 
be  allowed,  and  on  the  fifth  and  sixth  floors  150  pounds.  A  possible  weight  of  50 
pounds  per  square  foot  is  provided  for  in  the  roof  design. 

The  building  shown  in  Fig.  24  is  six  stories  high  besides  the  basement,  being 
50  feet  wide  by  165  feet  long.  Although  not  strictly  speaking  a  factory  building, 
the  design  is  typical  of  first-class  factory  construction. 

An  interesting  feature  of  the  layout  is  the  omission  of  the  first  floor  in  the 
corner  of  the  building  near  the  large  elevator,  in  order  to  provide  sufficient  head 
room  for  teams  to  drive  in  and  deposit  their  load  upon  the  elevator,  or  else,  if 
preferred,  to  drive  directly  on  to  the  elevator,  which  is  n  x  22  feet  in  area,  so  that 
the  wagon  and  horses  can  be  elevated  to  the  floor  where  the  goods  are  to  be 
placed  and  hauled  to  the  proper  point. 

The  designers  of  the  reinforced  concrete  and  also  the  builders  are  the  Eastern 
Expanded  Metal  Company,  of  Boston,  Mr.  J.  R.  Worcester  being  consulting 
engineer.  The  architect  is  Mr.  D.  A.  Sanborn,  of  Lynn. 

A  full  cross-section  of  the  warehouse,  showing  the  dimensions  of  the  mem- 
bers and  the  general  scheme  of  design,  as  shown  in'  Fig.  25.  Fig.  26  gives  typical 
floor  plan  and  also  detail  plan  and  sections  of  the  stairs. 

FLOOR  CONSTRUCTION. 

Round  rods  are  used  for  reinforcement  of  the  beams,  girders  and  columns, 
while  expanded  metal*  forms  the  slab  reinforcement. 

The  designs  were  carefully  worked  up  by  the  Eastern  Expanded  Metal  Com- 
pany and  checked  by  Mr.  Worcester  as  consulting  engineer.  The  sectional  view 
(Fig.  25)  clearly  illustrates  the  general  scheme  of  reinforcing.  Complete  details  of 
a  typical  girder,  beam  and  slab,  designed  to  safely  sustain  150  pounds  per  square 
foot  of  the  floor  load  in  addition  to  the  weight  of  the  concrete,  are  drawn  in  Fig.  27 
(page  79).  The  slab,  as  indicated,  is  6  feet  in  width  from  center  to  center  of  beam 

*  See  illustration,  Fig.  108,  page  182. 

75 


Fig.  25. — Cross-SectJon  Through  Lynn  Storage  Warehouse.      (See  p.  75.) 
76 


m 
Tl  ' 

Fig.  26. — Typical  Plan  and  Typical  Stair  Details  of  Lynn  Storage  Warehouse.      (See  p.  75.) 


11 


or  5  feet  3  inches  in  net  span.  The  beams  are  17  feet  9  inches  from  center  to  center 
of  girders  or  17  feet  net  span.  The  girders  are  12  feet  between  centers  of  columns 
or  \ol/2  feet  net  span. 

The  expanded  metal  reinforcement  is  placed  near  the  bottom  of  the  slab  in 
the  center  of  its  span,  and  rises  up  to  the  top  of  the  slab  over  the  beams  to  pro- 
vide for  negative  bending  moment.  The  metal  used  is  3-inch  mesh,  No.  10  gage, 
this  being  equal  to  a  cross-section  of  0.175  square  inches  per  foot  of  width  of  slab, 
or  0.5  per  cent,  of  the  cross-section  of  the  slab  area  above  the  steel. 

In  the  beams  three  i-inch  rods  are  imbedded,  one  of  them  bent  up  at  the 
quarter  points  and  running  horizontally  over  the  supports  so  as  to  lap  by  the  rod 
from  the  next  bay,  thus  giving  two-thirds  as  much  reinforcement  over  the  sup- 
ports as  in  the  center  of  the  beam.  The  stirrups  are  flat  steel  J4  mcn  by  I  inch. 
Notice  from  Fig.  25  that  in  the  three  lower  stories,  where  the  loading  is  heavier, 
there  are  five  stirrups  in  each  end  of  the  beam  instead  of  two.  The  beams 
in  these  lower  stories  are  made  the  same  size,  9  inches  by  20  inches,  in  order  to 
use  the  same  forms  throughout  the  building,  but  the  reinforcement  is  heavier. 

The  typical  girders  in  Fig.  27  have  five  ^-inch  rods  at  the  center,  two  of 
them  bent  up  and  running  on  an  incline  from  the  center  of  the  span.  The  incline 
starts  at  the  center  of  the  girder  instead  of  one-quarter  way  from  each  end,  be- 
cause the  girder  having  its  greatest  load  at  the  center,  the  shear  is  nearly  uniform 
throughout  the  entire  span. 

Instead  of  the  more  usual  practice  of  forming  the  wall  girders  as  a  part  of  the 
wall,  they  are  built  independently  of  the  wall  slab,  as  indicated  in  Fig.  25. 

FLOOR  SPECIFICATIONS. 

There  are  several  points  of  particular  interest  in  the  floor  specifications,  and 
without  copying  them  entire  a  brief  outline  is  worth  noting,  as  the  data  are  quite 
full  and  the  requirements  conservative. 

The  slabs  are  calculated  with  a  bending  moment  i/io  WL  in  cases  where 
three  or  more  slabs  are  continuous,  while  for  the  wall  slabs  J4  WL  is  employed. 
The  working  strength  of  the  concrete  in  compression  is  limited  in  the  slabs  to 
500  pounds  per  square  inch  if  computed  by  the  parabolic  method  of  stress,  which 
is  equal  to  about  600  pounds  by  the  more  usual  straight  line  method.  The  slab 
steel  is  limited  to  16,000  pounds  per  square  inch  in  tension,  the  ratio  of  the 
modulus  of  steel  to  that  of  concrete  being  taken  as  15.  At  right  angles  to  the 
length  of  the  span  i/io  square  inch  of  steel  is  required  per  foot  of  length  of  slab, 
which  with  the  4-inch  slab  is  equivalent  to  about  0.25  per  cent.  A  thickness  of 
M  inch  of  concrete  is  required  below  the  metal  in  the  slabs. 

The  bending  moment  in  the  beams  and  girders  is  considered  as  l/s  WL.  The 
beams  are  considered  as  T-beams  in  computing  their  strength,  and  it  is  specified 
that  the  width  of  the  flange  shall  not  exceed  one-third  the  span,  and  that  the 

78 


-.9' 


T3~.._ 


79 


average  compression  in  the  flange  shall  not  exceed  two-thirds  of  the  extreme  fiber, 
stress. 

The  vertical  shear  in  the  concrete  in  beams  which  are  not  reinforced  for  shear 
is  limited  to  one-tenth  the  extreme  compressive  working  stress  in  the  concrete, 
and  it  is  assumed  that  this  vertical  shear  is  distributed  over  a  section  whose  area 
is  the  width  of  the  stem,  that  is,  the  width  of  the  beam  multiplied  by  the  distance 
from  the  center  of  the  steel  to  the  center  of  the  slab,  the  latter  being  considered 
as  approximately  the  center  of  compression.  In  any  case  even  when  the  beam  is 
reinforced  for  shear  the  unit  shear  stress  is  limited  to  three-tenths  of  the  extreme 
compressive  unit  fiber  stress.  Thus,  if  the  allowable  compressive  fiber  stress  is 
500  pounds  per  square  inch-,  the  shear  in  beams  not  reinforced  for  shear  must  not 
exceed  50  pounds,  and  in  any  case  the  section  must  be  large  enough  so  that  even 
if  reinforced  there  is  sufficient  area  of  concrete  to  keep  the  total  shear  stress 
within  a  limit  of  150  pounds  per  square  inch. 

When  all  of  the  shear  cannot  be  taken  by  the  concrete,  the  vertical  component 
of  the  diagonal  bent-up  tension  rods  is  figured  to  take  it,  and,  in  addition,  if  neces- 
sary vertical  or  diagonal  stirrups  are  introduced. 

The  specifications  require  for  the  coarse  material  of  the  aggregate  trap  stone 
ranging  in  size  of  particles  from  Y$  inch  to  IJ4  inches.  The  proportions  for  the 
floor  system  are  1 :2l/2  -.5,  or  by  exact  volume  one  barrel  (4  bags)  cement  to  10 
cubic  feet  sand  to  20  cubic  feet  stone. 

FLOOR  SURFACE. 

The  floors  are  all  finished  with  a  granolithic  surface  I  inch  in  thickness,  and 
this  is  included  as  a  part  of  the  slab  thickness.  Thus,  if  the  plans  require  a  4-inch 
slab  the  lower  three  inches  are  of  1 :21A  15  concrete,  and  the  top  inch  is  granolithic. 
The  granolithic  surface,  which  is  composed  of  one  part  cement  to  i  part  sand  to  i 
part  %-inch  stone,  is  laid  before  the  concrete  below  it  has  set,  so  as  to  form  one 
homogeneous  slab. 

TEST  OF  FLOOR. 

At  an  age  of  thirty  days  it  is  specified  that  a  test  may  be  made  upon  the 
floor  panels  with  a  total  load  two  and  one-half  times  the  live  plus  the  dead  load. 

COLUMNS. 

The  columns  are  spaced  12  feet  apart  lengthwise  of  the  building  and  17  feet 
9  inches  on  centers  across  the  building.  The  interior  columns  supporting  the  lower 
floors  are  24  by  24  inches  and  25  by  25  inches  (the  larger  size  supporting  the 
greater  spans),  and  in  the  three  upper  stories  the  sizes  are  reduced  to  17  by  17 
inches  and  18  by  18  inches.  This  arrangement  was  used  to  avoid  remaking  the 
column  forms,  this  saving,  in  the  opinion  of  the  builders,  being  enough  to  more 
than  offset  the  slight  excess  of  concrete  required. 


81 


The  columns  are  outlined  in  Fig.  27  (p.  79)  and  also  quite  distinctly  in  the 
general  cross-section  in  Fig.  25  (p.  76).  In  the  latter  the  diagonal  rods  will  be 
noticed  at  the  head  of  each  column  running  into  the  beams  and  providing  diagonal 
reinforcement  against  wind  pressure.  The  building  is  so  high  in  proportion  to  its 
width  that  this  reinforcement  was  considered  advisable. 

The  ordinary  reinforcement  of  the  columns  is  four  j^-inch  vertical  rods,  with 
occasional  hoops  J4  inch  in  diameter.  In  the  wall  columns,  which  are  oblong  in 
plan  and  which  because  of  their  location  are  subjected  to  a  greater  wind  pressure, 
four  larger  vertical  rods  are  inserted.  The  rods  are  of  such  length  as  to  project 
above  the  next  floor  level,  and  the  next  set  rests  upon  this  floor  so  as  to  lap  and 
transfer  the  stresses. 

The  columns  are  laid  with  a  richer  concrete  than  other  parts  of  the  building, 
being  mixed  in  proportions  1:1^2:3.  The  compressive  stress  allowed  is  700  pounds 
per  square  inch  figured  on  the  area  of  the  column,  or  600  pounds  per  square 
inch  on  the  concrete  if  the  steel  is  computed  to  take  a  proportion  of  the  com- 

pression'  CONSTRUCTION. 

Four  very  good  views  are  presented  in  Figs.  28,  29,  30,  31,  showing  the 
progress  from  the  first  story  to  the  stage  where  the  roof  is  laid  and  wall  panels 
are  nearly  completed. 

Fig.  28  (p.  81)  shows  the  first  story  columns  and  beam  molds  in  place,  and  in 
the  distance  the  setting  of  the  second-story  column  molds.  The  framework  for  the 
elevator  which  hoists  the  concrete  to  place  also  appears  on  the  farther  side  of  the 
building. 

Fig.  29  is  taken  after  the  completion  of  the  concrete  work  of  the  fifth  floor. 
The  forms  are  removed  from  the  columns  and  floor  of  the  lower  stories,  but  the 
supports  are  still  left  under  the  beams  and  girders  of  the  fourth  floor.  The  wall 
panels  are  completed  in  the  first  story  and  the  forms  for  the  second  story  panels 
are  in  place  on  the  side  of  the  building. 

The  view  in  Fig.  30  was  taken  when  the  building  was  one  story  higher,  and 
shows  more  clearly  the  elevator  for  hoisting  the  concrete,  the  mixer  being  located 
just  at  the  foot  of  it.  The  reinforcement  for  wall  panels  is  quite  clearly  shown, 
this  being  set  in  place  before  the  panel  forms  are  adjusted. 

Fig.  31  shows  the  building  with  the  roof  on  and  most  of  the  panel  work 
complete. 

A  photograph  of  the  building  complete  is  shown  in  Fig.  24  at  the  beginning 
of  the  chapter. 

The  construction  was  begun  about  July  i,  1906,  and  was  practically  complete 
December  ist,  although  the  cold  weather  caused  some  delay  beyond  this  time 
in  completing  the  panels.  The  average  rate  of  progress  on  the  forms  and  struc- 
tural concrete  after  the  work  was  well  started  was  ten  days  per  story. 

The  concrete  was  mixed  on  the  ground  in  a  rotary  mixer  (see  Fig.  30),  and  a 

82 


Fig.  30.— Lynn  Storage  Warehouse  at  Sixth  Floor  Level.      (See  p.   82.) 
84 


hoist  elevated  the  concrete  and  dumped  it  into  the  hopper,  from  which  it  was 
conveyed  by  large  two-wheel  barrows  and  dumped  in  place.  Approximately  2,000 
cubic  yards  of  concrete  were  laid  in  the  structure  and  136  tons  of  steel  were  used 
in  the  reinforcement.  This  was  delivered  at  the  factory  of  the  builders,  where  it 
was  bent  to  the  shape  required,  the  ends  of  the  tension  rods  being  also  bent  hot  at 
right  angles  to  give  a  better  grip  in  the  concrete. 

In  placing  the  steel  the  stirrups  were  set  first,  and  as  these  were  in  the  shape 
of  a  U  with  the  ends  bent  over  on  a  curve,  these  ends  rested  upon  the  slab  forms, 
thus  forming  a  rest  for  the  tension  rods  which  were  placed  within  them  and  sup- 
ported at  the  proper  distance  above  the  bottom  of  the  beam. 

FORMS. 

For  the  forms  spruce  lumber  was  generally  employed.  However,  a  good 
quality  of  North  Carolina  pine,  tongued  and  grooved,  was  used  for  the  panels,  this 
being  preferable  to  spruce  because  less  apt  to  warp  and  having  a  harder  surface, 
which  splinters  less  and  does  not  soak  so  much  water.  In  all  about  182,000  feet 
board  measure  of  lumber  were  used  in  the  construction  of  the  building. 

Only  one  set  of  forms  was  required  above  the  first  floor,  the  forms  thus  being 
used  six  times.  Although  a  story  was  completed  on  the  average  in  ten  days, 
the  work  was  carried  on  from  end  to  end  of  the  building,  so  that  one  end  of  the 
floor  system  had  hardened  sufficiently  to  allow  removal  of  the  forms  for  use  in 
the  floor  above,  while  the  other  end  of  the  floor  was  being  laid.  The  beams  and 
girder  forms  were  constructed  as  U  units,  that  is,  the  sides  and  bottom  were 
fastened  together,  and  by  slightly  beveling  the  sides  the  form  was  easily  lowered. 

By  reference  to  the  plan  in  Fig.  25  (p.  76)  it  will  be  seen  that  although  the 
allowable  loading  varied  on  different  floors,  the  dimensions  of  the  beams  were 
maintained  the  same  throughout  except  for  those  supporting  the  roof,  the  differ- 
ence in  the  strength  being  provided  for  by  varying  the  reinforcement. 

The  general  plan  followed  in  removing  the  forms  was  to  leave  column  forms 
two  days,  slab  forms  six  days  and  beam  forms  six  days.  The  shoring,  however, 
was  left  under  the  beams  and  girders  for  three  or  four  weeks  to  guard  against  pos- 
sibility of  accident.  Of  course  these  periods  were  varied  according  to  the  con- 
ditions of  the  weather  and  the  hardening  of  the  concrete,  but  they  represent  the 
ordinary  minimum  time. 

Petrolatum  was  used  for  greasing  the  forms. 

The  usual  gang  consisted  of  one  superintendent,  3  foremen,  8  men  at  the 
mixing,  one  engineman,  12  men  placing  concrete,  3  steel  men  and  30  to  60  car- 
penters, the  larger  number  being  required  for  the  first  set-up  of  the  forms,  while 
the  smaller  number  was  sufficient  for  simply  raising  them  to  a  floor  above  when 
there  was  no  appreciable  change  in  the  design. 

86 


WALL  CONSTRUCTION. 

Panels  were  built  as  a  separate  operation  from  the  rest  of  the  concrete  work, 
as  shown  in  the  photographic  illustrations.  The  exterior  columns  were  carried  up 
at  the  same  time  as  the  floors,  and  the  wall  panels  afterward  filled  in  between  them. 
The  wall  panel  reinforcement  consisted  of  ^  inch  diameter  rods,  the  horizontal 
rods  being  spaced  12  inches  apart  and  the  vertical  rods  24  inches  apart.  This  steel 
was  first  placed,  as  shown  in  Figs.  29  and  30,  and  after  setting  the  window  frames, 
the  forms,  consisting  simply  of  2  inch  by  4  inch  studs  with  i-inch  boards  nailed 
to  them,  were  set,  and  the  concrete  poured,  running  into  grooves  left  in  the 
columns.  In  Fig.  31  the  difference  in  the  color  of  the  freshly  laid  and  the  old  con- 
crete is  apparent,  the  concrete  becoming  lighter  as  the  water  dried  out.  The  walls 
were  completed  with  slapdash  or  stippled  finish,  illustrated  in  Fig.  129,  page  198. 

PARTITIONS. 

Around  the  elevators  and  stairs  and  also  to  enclose  the  offices  on  the  first 
floor  and  storage  rooms  on  the  fifth  floor,  expanded  metal  partitions  were  em- 
ployed. Expanded  metal  lathing,  No.  24  gage,  was  wired  to  i-inch  channel  bars 
placed  vertically  12  inches  on  centers,  and  the  lathing  then  plastered  with  five 
coats  so  as  to  form  a  solid  partition  2  inches  thick. 

The  first  or  scratch  coat  consisted  of  one  part  cement  to  3  parts  of  lime  with  the 
usual  quantity  of  sand  and  hair.  This  pressed  through  the  lathing,  so  that  it  could 
be  plastered  on  both  sides  with  a  brown  coat  of  lime  and  cement  mortar  in  pro- 
portions i  part  cement  to  3  parts  of  lime  mortar  and  followed  by  a  finishing  coat 
of  the  same  mortar  on  both  sides. 

WATERPROOFING. 

To  meet  the  requirement  that  the  basement  should  be  very  dry,  asphaltum 
waterproofing  was  laid,  as  indicated  by  the  solid  black  line  in  Fig.  25  (p.  76)  to  pre- 
vent penetration  of  ground  water.  The  ground  having  been  thoroughly  tamped,  a 
layer  of  concrete  was  spread  upon  it  and  the  wall  slab  placed.  Then  on  top  and 
inside  of  this  layer  of  concrete,  five-ply  asphaltum  waterproofing  was  spread  and 
upon  this  3  inches  of  concrete  with  granolithic  surface. 


87 


CHAPTER  VII. 


BULLOCK  ELECTRIC  MACHINE  SHOP. 

A  novel  feature  of  the  reinforced  concrete  machine  shop  of  the  Bullock  Elec- 
tric Company,  at  Norwood,  Ohio,  a  branch  of  the  Allis  Chalmers  Company,  is  the 
supporting  of  lo-ton  cranes  upon  concrete  brackets  which  form  a  part  of  the 
concrete  column.  It  is  customary  even  in  reinforced  concrete  shops  to  place  the 
crane  runs  upon  steel  columns  independent  of  the  rest  of  the  structure,  but  we 
have  here  an  example  of  the  transmission  of  the  load  directly  from  the  runways, 
which  are  steel  plate  girders,  to  the  reinforced  concrete  columns.  The  machine 
shop,  illustrated  in  Fig.  32,  was  only  fifty-eight  and  a  half  days  in  building  and  has 
been  in  successful  and  continuous  operation  since  its  completion  early  in  1906. 

The  building  under  consideration  is  an  extension  to  Shop  No.  3,  which  is  of 
the  regular  type  of  steel  frame  with  brick  walls.  The  extension  was  first  designed 
in  similar  steel  construction,  but  an  alternate  proposal  to  substitute  reinforced 
concrete  made  by  the  Ferro  Concrete  Construction  Company,  of  Cincinnati,  was 
adopted  at  substantially  the  same  cost. 

DESIGN. 

The  general  design  of  the  building  is  shown  in  the  cross-section  in  Fig.  33, 
and  a  partial  elevation  in  Fig.  34. 

The  lower  story  is  devoted  to  the  manufacture  of  the  heavier  part  of  the  elec- 
tric machinery  and  in  the  assembling  of  dynamos.  In  the  upper  story  are  the 
lighter  machine  tools  for  the  making  of  the  smaller  parts.  The  roof  is  of  2-inch 
plank  upon  steel  trusses  (see  Fig.  33),  being  built  in  this  way  instead  of  in  rein- 
forced concrete  so  that  it  can  be  raised  and  a  third  story  added  when  needed. 
One  end  of  the  building,  as  shown  in  the  photograph  of  the  completed  shop,  Fig. 
32,  is  also  of  temporary  construction,  so  that  it  can  be  lengthened  without  tearing 
down  a  brick  and  concrete  wall. 

Twisted  steel  was  used  for  reinforcement.  The  proportions  of  the  concrete 
were  i  :2  -.4  throughout,  using  4  bags  Atlas  Portland  cement  to  8  cubic  feet  of  good 
coarse  sand  to  16  cubic  feet  of  broken  stone,  which  was  the  run  of  the  crusher, 
screened  through  a  1%-inch  screen. 

The  floors  (see  Fig.  33)  consist  of  three  longitudinal  bays  running  the  entire 
length  of  the  building,  a  distance  of  256  feet.  The  total  width  is  107  feet  jV2 
inches,  thus  allowing  the  two  outer  bays  to  be  each  42  feet  i\l/2  inches  and  the 
inside  bay  21  feet  8*A  inches.  In  the  other  direction,  that  is,  lengthwise  of  the 

89 


building,  the  columns  are  16  feet  apart  on  centers.  The  long  open  floor  spaces 
afford  ample  room  for  the  machine  tools  and  the  handling  and  distributing  of 
the  parts  and  the  finished  machines.  A  view  of  the  shop  in  operation  is  photo- 
graphed in  Fig.  35. 

The  height  of  the  first  story,  27  feet  in  the  clear  from  the  floor  to  the  ceiling 
and  23  feet  in  the  clear  to  the  bottom  of  the  girders,  provides  the  head  room 
necessary  for  the  xo-ton  cranes  which  are  located  in  the  outside  bays,  and  also  per- 
mits very  large  high  windows. 

The  center  bay  is  designed  so  that  another  crane  may  be  installed  there  when 
required,  but  for  the  present  its  place  is  occupied  by  an  intermediate  floor.  This 
floor  is  of  light  steel  I-beam  and  wood  construction,  resting  upon  channel  irons 
running  across  between  the  two  rows  of  columns.  The  channels  are  bolted  at  the 
ends  to  the  concrete  columns  and  their  weight  also  supported  by  straps  suspended 


Fig.  34. — Side  Elevation  of  the  Bullock  Machine  Shop.      (See  p.  89.) 

from  the  crane  brackets.  Had  the  floor  been  intended  for  permanent  use  it  would 
have  been  built  of  reinforced  concrete,  but  the  difficulty  and  expense  of  tearing 
down  a  floor  of  concrete  when  the  space  was  needed  for  the  crane  made  this  im- 
practicable. 

91 


COLUMNS. 


Footings  of  the  interior  columns  are  shown  in  Fig.  36.  These  illustrate  a 
typical  reinforced  concrete  footing  with  two  layers  of  rods  at  right  angles  to  each 
other  in  the  bottom.  In  this  case  the  rods  are  24  inch  diameter,  while  in  the 
footings  for  the  wall  columns,  which  are  not  shown  in  our  drawings,  J^-inch  rods 


,i  WH- 

LI  11X4. 4-4-4-4- 

li&ita 


FJg.  36.— Reinforced   Footings  for  Interior  Columns.      (See  p.  93 •) 

fulfil  the  requirements.  The  rods  in  each  layer  are  shorter  than  the  dimensions  of 
the  footing  in  the  interior  columns  (Fig.  36),  being  6  feet  8  inches  long  and  placed 
with  one  end  2  inches  from  the  edge  of  the  footing  and  the  other  end  18  inches 
from  the  opposite  edge,  the  alternate  rods  being  staggered  to  allow  for  the  de- 
crease in  the  bending  moment  from  the  column  toward  the  edges  of  the  footing. 
As  the  footing  is  square,  while  the  column  is  oblong,  10  bars  run  in  one  direction, 
while  12  bars  are  placed  in  the  other  layer  to  provide  for  the  greater  bending 
moment. 

The  footings  really  extend  up  to  within  3  inches  of  the  first  floor  level,  the 
short  vertical  section  of  2  feet  n  inches  being  built  at  the  same  time  as  the  footing 
proper  in  order  that  the  first  floor  can  be  laid  entire  and  the  first  story  columns 


started  above  it.  These  short  vertical  lengths  are  reinforced  with  six  i-inch  rods 
which  extend  4  inches  down  into  the  main  part  of  the  footing  and  project  7  inches 
above  the  concrete  so  as  to  pass  through  the  floor  and  connect  with  the  column 
above.  These  vertical  rods  rest  upon  steel  plates  3  inches  square,  which  dis- 
tribute the  compression  from  the  steel  to  the  concrete.  Four  J^-inch  horizontal 
hoops  are  placed  around  the  vertical  rods.  The  columns  above  the  first  floor 
are  of  slightly  smaller  dimensions,  as  shown  by  the  offsets  in  Fig.  33.  Thus,  the 
portion  below  the  first  floor  is  21  by  27  inches,  which  reduces  to  18  by  24  inches 
with  a  further  reduction  above  the  crane  brackets.  The  reinforcement  in  the 
columns  in  the  first  story  is  the  same  as  below  the  floor,  six  i-inch  rods  butting 
upon  the  ends  of  the  rods  below  and  connected  with  them  by  a  short  pipe  sleeve. 
One-quarter-inch  hoops  were  spaced,  double,  every  12  inches. 

The  wall  columns  have  footings  similar  to  those  of  the  interior  columns,  except 
of  smaller  dimensions  and  lighter  reinforcement.  The  base  is  7  feet  4  inches,  rein- 
forced with  sixteen  ^-inch  rods  in  each  layer.  Below  the  first  floor  the  column  is 
20  inches  by  26  inches,  reinforced  simply  with  a  ^-inch  rod  in  each  corner  and 
four  %-'mch  horizontal  hoops. 

Above  the  first  floor  the  exterior  columns  are  of  T-shaped  cross-section,  as 
described  in  the  paragraphs  which  follow,  the  column  proper  being  14  by  22  inches 
in  the  first  story  and  12  by  14  inches  in  the  second  story. 

CRANE  BRACKETS. 

The  brackets,  shown  in  Fig.  33  (p.  90),  which  support  the  cranes  are  of  particu- 
lar interest.  To  provide  for  the  shear,  it  was  considered  advisable  to  loop  the  rein- 
forcing rods  into  the  bracket,  running  them  out  horizontally  and  then  bending 
them  down  on  an  incline  back  into  the  column.  The  steel  I-beams  supporting  the 
track  for  the  crane  rest  directly  upon  these  brackets  and  run  the  full  length  of  the 
building. 

FLOOR  SYSTEM. 

The  floor  of  the  first  story  was  laid  directly  upon  the  ground  after  filling 
in  around  the  columns  and  thoroughly  puddling  the  earth.  This  floor  is  of  i  :2  -.4 
concrete  with  sleepers  upon  it  and  a  2-inch  oak  floor. 

The  second  floor  is  supported  in  the  two  bays  by  girders  about  40  feet  long  in 
the  clear,  12  inches  wide  and  54^2  inches  deep  from  top  of  slab.  In  the  bottom 
of  the  girder,  to  take  the  tension,  are  ten  i-inch  square  twisted  rods  and,  to  pro- 
vide for  the  negative  bending  moment,  five  i-inch  rods  were  placed  at  the  top  of 
the  beams  over  the  supports.  The  shear  or  diagonal  tension  is  provided  for  by 
these  bent-up  rods,  together  with  sixteen  ^2-inch  and  ten  J4~mcn  U  bars.  The 
reinforcement  was  rigidly  located  before  the  concrete  was  poured,  so  that  it  could 
not  be  displaced. 

In  the  central  bay  the  net  span  is  about  20  feet  and  the  girders  are  smaller, 
being  6  by  31  inches.  The  thickness  of  the  slab  is  included  in  the  depth  of  the 

94 


girders  in  both  cases,  since  the  concrete  for  the  girders  and  slabs  was  poured  at 
one  operation. 

The  girders  extend  across  the  building  from  column  to  column,  and  are  thus 
16  feet  apart  on  centers,  giving  a  net  span  for  the  concrete  floor  slab  of  15  feet  in 
the  outside  bays  and  15  feet  6  inches  in  the  middle  bay.  The  slabs,  which  are  de- 
signed by  a  load  of  225  pounds  per  square  foot,  are  7^  inches  thick,  reinforced 
with  J/2-inch  bars  spaced  6  inches  on  centers.  In  addition  %-inch  rods  about  2 
feet  apart  run  across  the  building  parallel  to  the  girders  to  prevent  contraction 
cracks. 

The  wearing  surface  of  the  floor  is  ^-inch  maple  flooring  upon  3  by  4-inch 
sleepers  spaced  16  feet  apart  on  centers  and  filled  between  with  cinder  concrete. 

WALLS. 

The  window  area  comprises  a  large  percentage  of  the  wall  surface,  the  open- 
ings in  the  concrete  being  12  feet  2  inches  wide  and  in  the  lower  story  23  feet  8 
inches  high.  The  walls,  4  inches  in  thickness,  were  carried  up  at  the  same  time 


Fig.  37.— Tongs  for  Bending  Light  Steel  Bars.     (See  p.  96.) 

as  the  columns,  thus  forming  with  them  T-sections,  as  shown  in  Section  GG, 
Fig.  34.  Below  and  above  the  windows,  the  wall  was  also  4  inches  thick,  with 
water  table  and  sills,  as  in  Fig.  33.  The  window  sills,  which  are  5  inches  thick, 
were  poured  as  a  part  of  these  walls  and  were  thoroughly  troweled  on  the  top 

95 


before  the  concrete  had  set  hard,  so  as  to  form  a  surface  like  that  on  a  sidewalk. 

Each  vertical  section  of  wall  was  reinforced  with  two  ^-inch  square  bars  in 
the  first  story  and  two  J^-inch  t>ars  in  the  second  story.  Horizontal  loops  of 
j4-inch  wire  were  also  placed  about  2  feet  apart.  Above  the  windows  the  walls 
were  reinforced  with  three  horizontal  rods  and  with  vertical  rods  spaced  about  3 
feet  apart.  Fig.  34  (p.  91),  which  is  a  side  elevation  of  two  bays,  illustrates  more 
clearly  the  placing  of  the  wall  reinforcement. 

In  order  that  the  exterior  of  the  new  building  should  harmonize  with  the 
older  shops  in  the  same  plant,  the  walls  were  surfaced  with  a  single  thickness  of 
light-colored  pressed  brick.  These  were  tied  to  the  wall  by  the  wires  which  were 
used  in  keeping  the  forms  together.  These  ties  were  No.  8  galvanized  iron  wire 
about  12  inches  long,  which  projected  from  the  concrete  about  6  inches.  They 
were  spaced  every  18  inches  horizontally  and  every  six  courses  of  brick  vertically. 
The  projecting  ends  were  turned  in  a  hook  by  the  bricklayer  and  bedded  in  the 
mortar  joints  just  like  regular  brick  anchors. 

CONSTRUCTION  PLANT. 

In  accordance  with  their  usual  plan  in  building  construction,  the  contractors 
erected  near  the  site  a  carpentry  shop  about  20  feet  by  42  feet,  with  an  adjoining 


Fig.  38.  —  Power  Bender  lor  Large  Steel  Bars.     (See  p.   98.) 


tool  room.  In  the  shop,  wood  working  tools,  including  a  circular  saw  and  a 
planer,  were  installed  and  driven  by  electric  motor  from  power  furnished  by  the 
town  plant.  Here  all  the  forms  were  prepared. 


The  steel  was  also  bent  in  this  shop.  For  the  small  rods  of  the  floor  slabs  a 
heavy  pair  of  tongs  was  used,  with  three  projecting  lugs,  as  shown  in  Fig.  37 
(P-  95)-  Tne  heavy  steel  for  the  beams  and  girders  was  bent  by  power  in  a 
machine  consisting  essentially  of  a  face  plate  with  a  roller  projecting  from  it,  which, 
when  the  power  is  applied,  bends  the  bar  around  the  spindle.  The  sketch  in  Fig. 
38  (p.  96)  illustrates  the  operation. 

The  layout  of  the  construction  plant  and  its  relation  to  the  machine  shop 
are  illustrated  in  Fig.  39.  The  broken  stone,  sand  and  cement  were  brought  in 
railroad  cars  and  stored  in  bins  close  to  the  tracks.  The  mixing  plant  was  pro- 


Fig.  40. — Sectional   Plan   and   Elevation  of  Girder  Molds.      (See .p.  100.) 

vided  with  both  a  Ransome  and  a  Smith  mixer,  although  most  of  the  time  one  of 
these  machines  was  of  sufficient  capacity  to  supply  the  concrete.  The  materials 
were  wheeled  along  the  runway  on  the  platform,  from  which  they  were  dumped 
into  the  mixers.  From  the  mixers  the  concrete  was  brought  to  the  place  where 
used,  in  two-wheel  barrows  of  Ransome  type,  but  with  staggered  wheel  spokes, 
these  having  been  found  to  be  better  than  the  single  row  of  spokes.  Each  of 
these  held  about  5  or  6  cubic  feet  of  concrete.  The  hoist  consisted  of  a  single 
platform  double-barrow  hoist,  taking  two  barrows  up  at  one  time,  and  from  the 
hoist  the  concrete  was  wheeled  to  place  upon  a  runway  raised  above  the  steel,  so  as 
not  to  interfere  with  it,  and  dumped  directly  in  place. 

The  cost  of  the  construction   plant,   not  including  small   tools,    shovels,   etc., 
was  $4,350-     In  the  building  2,300  barrels  of  cement  were  used. 


GANG. 

The  usual  gang  consisted  of  about  fifty  laborers  and  fifty  carpenters.  The 
men  engaged  directly  upon  the  building  were  distributed  approximately  as  follows : 

Four  foremen. 

Twelve  men  mixing  concrete. 

Six  men  hoisting  concrete. 

Fifteen  men  placing  concrete. 

Seven  men  bending  and  placing  steel. 

One   engineman. 

Fifty  carpenters. 

The  regular  rate  of  pay  for  the  laborers,  who  were  experienced  concrete  men, 
was  $2  per  day  of  ten  hours. 


of  Co/umn  0and5 


f&rf  £/ev&f/on  of  Co/u/??/?  Mou/d 


Fig.  41. — Details  of  Column  Molds.      (See  p.  100.) 

FORMS. 

The  forms  were  built  of  yellow  pine,  which  cost  $20  per  thousand.  As  the 
building  was  only  two  stories  high,  much  of  the  lumber  could  be  used  only  once, 
although  some  of  the  wall  and  column  forms  were  used  twice.  The  lumber  cut  to 
such  good  advantage,  however,  that  much  of  it  could  be  used  on  another  job,  and 
the  builders  estimated  the  salvage  at  about  30  per  cent.,  that  is,  it  might  be 
assumed  that  three-fifths  of  the  lumber  could  be  used  to  good  advantage  on 
another  building,  and  that  the  value  of  this  was  one-half  of  its  original  price. 

99 


The  panel  boards  were  planed  one  side  and  on  the  edges.  For  the  beam  and 
column  molds  I  by  6-inch  tongued  and  grooved  stock  was  employed. 

The  construction  of  the  girder  molds  is  shown  in  Fig.  40  (p.  98),  and  the 
column  molds  more  in  detail  in  Fig.  41.  The  column  bands  or  clamps  were  2  by 
4-inch  stuff,  held  together  by  blocks  and  wedges,  as  shown  in  the  drawing.  On  one 
side  the  piece  was  loose,  so  that  the  same  clamp  could  be  used  for  a  narrower 
column  by  changing  the  position  of  the  blocks.  The  clamps  were  spaced  18  inches 
apart  near  the  bottom  of  the  column,  reducing  to  24  inches  apart  near  the  top. 

The  girder  forms  consisted  essentially  of  i-inch  paneled  sides,  the  boards  bat- 
tened together  with  pieces  of  2  by  4-inch  stuff,  and  a  bottom  of  1 24-inch  plank, 
which  was  supported  in  part  by  I  by  3-inch  cross  pieces  nailed  to  the  end  of  the 
batten  strips,  and  in  part  by  the  shores  or  struts  resting  upon  the  floor  below. 
A  i  by  6-inch  strip  nailed  to  the  upper  part  of  the  battens  supported  i  by  6-inch 
joists,  upon  which  rested  the  slab  flooring. 

The  shores  or  struts,  instead  of  being  a  single  piece  of  lumber,  were  made 
of  I-section  by  nailing  together  three  pieces  of  2  by  6-inch  plank,  as  shown  in 
section  AA,  Fig.  40.  This  plan  was  followed  because  the  first  story  was  so  high 
that  an  ordinary  4  by  4-inch  post  would  have  been  liable  to  spring  unless  braced 
very  frequently  in  its  height.  An  exterior  view  of  the  building  during  construc- 
tion, showing  the  column  and  girder  forms  and  bracing,  is  given  in  Fig.  42. 

The  forms  of  the  walls,  columns  and  panels  were  left  in  place  about  two  weeks 
and  the  shores  six  weeks.  This  time  was  longer  than  is  customary,  but  in  this 
building  the  spans  were  so  long  that  the  dead  weight  of  the  concrete  was  excep- 
tionally large,  and  this  threw  a  large  proportion  of  the  total  load  upon  the  con- 
crete when  the  forms  were  first  taken  down. 


100 


101 


102 


CHAPTER  VIII. 


WHOLESALE  MERCHANTS'  WAREHOUSE. 

The  immense  reinforced  concrete  warehouse  at  Nashville,  Tenn.,  illustrated 
on  the  opposite  page,  is  the  result  of  a  scheme  of  co-operation  of  a  number  of  the 
most  prominent  merchants  of  that  city.  They  previously  had  conducted  their 
business  in  various  individual  warehouses  in  the  business  section  of  the  city  and 
some  distance  from  the  railroad.  To  better  their  condition  the  idea  was  conceived 
of  forming  the  Wholesale  Merchants'  Warehouse  Company  to  erect  a  fireproof 
building  alongside  of  the  tracks,  and  thus  save  the  large  expense  of  hauling  and 
at  the  same  time  obtain  greatly  reduced  insurance  rates. 

Insurance  on  the  stock  carried  by  the  merchants  in  the  old  type  of  frame' 
buildings  ranged  from  $1.80  to  $2.20  per  hundred  while  in  the  new  fireproof,  rein- 
forced concrete  structure  the  rates  were  reduced  to  $0.40  per  hundred. 

To  provide  enough  floor  space  not  only  for  storage  but  also  for  carrying  on 
the  wholesale  shipments,  the  building  is  500  feet  long  by  132  feet  deep  and  four 
stories  high,  with  basement  and  sub-basement.  It  is  divided  by  walls  of  concrete 
blocks  into  compartments  entirely  separate  one  from  the  other,  each  compart- 
ment comprising  a  complete  wholesale  warehouse,  and  as  the  building  is  located 
not  only  near  the  railroad  but  in  the  central  part  of  the  city  as  well,  it  constitutes 
the  sole  place  of  business  in  the  city  for  each  firm. 

The  basement  is  paralleled  by  two  railroad  tracks,  an  extension  of  the  base- 
ment floor  forming  the  unloading  platform.  A  wide  trucking  platform  also  runs 
through  the  basement,  reaching  all  the  elevators. 

Reinforced  concrete  was  adopted  because  of  the  estimated  economy  in  cost 
and  in  time  of  construction.  The  designing  architects  were  Messrs.  McDonald 
&  Dodd;  the  supervising  architect,  Mr.  Hunter  McDonald,  and  the  engineer,  Mr. 
W.  H.  Burk.  The  Oliver  Company  were  the  builders. 

Corrugated  bars*  were  used  throughout  the  building,  and  the  Expanded 
Metal  and  Corrugated  Bar  Company  approved  the  plans  as  drawn. 

LAYOUT. 

The  general  plan,  Fig.  44  (p.  105),  is  a  framing  plan,  showing  the  layout  of  the 
beams  and  also  illustrating  the  division  of  one  of  the  floors  into  the  compartments 
for  the  different  firms.  The  interior  columns  are  spaced  12  feet  apart  in  one  direc- 
tion and  16  feet  7^  inches  in  the  other.  In  general,  the  beams  run  lengthwise  of  the 


*  See  Fig.  103,  page  179. 

103 


building  from  column  to  column,  with  no  supporting  girders,  while  cross  beams 
are  placed  at  intervals  to  tie  the  building  together  and  to  support  the  partitions. 

These  cross  beams  and  their  partitions  are  not  spaced  uniformly,  but  at 
different  distances  apart,  so  as  to  afford  a  merchant  a  choice  of  several  sizes  of 
rooms,  each  of  which  extends  the  full  depth  of  the  building.  For  example,  the 
spacing  of  the  partitions  is  three  bays  in  a  large  number  of  cases,  while  in  one 
portion  of  the  building  the  spacing  is  one  and  a  half  bays ;  in  another,  two  bays ; 
and  in  still  another  four  bays.  The  widths  of  the  compartments  thus  vary  from 
about  24  feet  to  66  feet,  with  a  uniform  depth  of  about  130  feet. 

The  beam  design  is  somewhat  different  from  usual  along  the  front  and  rear 
of  the  building.  Here  the  cross  span  is  18  feet  instead  of  12  feet,  and  short 
cross  girders  are  introduced,  each  of  which  supports  a  floor  beam  at  its  center. 
The  projecting  girders  at  the  rear  of  the  building,  that  is,  at  the  top  of  the  plan 
in  the  figure,  support  the  roof  over  the  loading  platform  in  the  basement. 

A  cross  section  of  the  building  is  given  in  Fig.  45  (p.  106),  showing  the  columns 
and  the  outline  of  the  beams  and  slabs.  In  order  to  take  advantage  of  the  full  width 
of  the  lot,  and  yet  not  encroach  upon  the  loading  platform  with  the  basement 
columns,  the  rear  wall  of  the  building  from  the  first  floor  up  to  the  roof  is  sup- 
ported by  the  ends  of  the  floor  girders  which  project  at  each  story  about  30 
inches,  thus  acting  as  cantilevers. 

Because  of  the  variety  in  the  weights  of  the  goods  to  be  stored,  the  floors 
were  designed  for  different  loadings.  The  first  floor  was  calculated  for  350 
pounds  loading  per  square  foot  of  surface,  the  second  floor  for  300  pounds  and 
the  third  and  fourth  floors  for  250  pounds.  The  roof  was  figured  for  a  snow  load 
of  40  pounds  per  square  foot.  These  figures  in  each  case  represent  live  loads, 
and  do  not  include  the  weight  of  the  concrete  itself. 

BEAMS  AND  SLABS. 

Details  of  the  construction  of  a  typical  beam  and  slab  are  drawn  in  Fig.  46 
(p.  107).  These  are  designed  for  the  first  story  to  support  a  floor  load  of  350 
pounds  per  square  foot  in  addition  to  the  weight  of  the  reinforced  concrete  itself. 

Inspection  of  the  plans  shows  that  three  of  the  six  bars  in  the  beam  are 
bent  up  on  an  incline  and  run  across  over  the  supports,  lapping  there  a  distance 
of  one-quarter  of  the  span  length.  Several  3/i6-inch  round  stirrups  are  also  pro- 
vided to  assist  in  taking  the  shear.  The  dimensions  of  the  beams,  12  by  20 
inches  for  the  longitudinal  beams  of  which  the  details  are  shown,  and  10  by  16 
inches  for  the  cross  beams  supporting  the  partitions,  are  given  in  the  customary 
way,  measuring  the  depth  from  the  top  of  the  slab  to  the  bottom  of  the  beam,  and 
assuming,  of  course,  that  the  standard  practice  is  followed  of  placing  the  concrete 
in  the  beams  and  slabs  at  one  time,  so  as  to  form  a  monolithic  T-section.  The 
rods  in  the  bottom  of  the  beam  are  placed  in  two  layers,  so  as  to  bring  them  far 
enough  apart  to  prevent  the  concrete  splitting  between  them. 

104 


9t//j  £u/f?//nff- 


~\ 


MOj7<?£i 
105 


% 


m&BT/         »/£/,—/ 


106 


It  will  be  noticed  in  the  floor  sketched,  that  ^-inch  bars  5  inches  apart  to  form 
the  reinforcement  for  the  slab,  are  placed  in  the  bottom  of  the  slab  at  the  center 
of  its  span,  but  that  all  run  up  toward  the  supporting  beam,  and  thus  in  the 
longitudinal  section  of  the  beam  at  the  top  of  the  diagram  these  rods,  which  are 
shown  by  so  many  dots,  are  close  to  the  upper  surface.  This  plan  is  somewhat 
easier  to  follow  than  where  rods  are  alternately  horizontal  and  bent  up,  and  it  is 
preferable  to  the  latter  because  the  negative  bending  moment  at  the  ends  of  a  con- 
tinuous slab  is  at  least  as  great  as  the  positive  moment  in  the  center,  so  that  fully 
as  much  reinforcement  is  required  to  take  the  pull  at  the  top  of  the  slab  over  the 
supports  as  is  necessary  in  the  bottom  at  the  middle  of  the  span. 

The  roof  is  of  concrete  of  lighter  design,  and  the  slab,  which  is  3  inches  thick, 
is  laid  on  a  slope  of  %  inch  per  foot  and  is  covered  with  tar  and  gravel  roofing. 

A  detail  of  the  beams  around  elevator  walls  is  drawn  in  Fig.  47. 


Fig.  46. — Details  of  Reinforcement  of  Typical  Beam  and  Slab.      (5Ve  p.  104.) 

COLUMNS. 

Although  the  floor  loads  are  heavy,  the  columns  are  only  19  inches  square 
in  the  basement  and  less  than  this  in  the  stories  above  because  the  spacing  be- 
tween them  is  comparatively  small.  The  general  type  of  reinforcement  is  four 
5^-inch  vertical  bars  near  the  corners,  with  3/i6-inch  horizontal  loops  at  intervals 
of  5  to  12  inches,  varying  with  the  dimensions  of  the  columns.  In  the  first  story 
24-inch  vertical  bars  were  used  with  loops  4  inches  apart. 

The  columns  are  designed  for  a  loading  of  750  pounds  per  square  inch,  a 
seemingly  high  stress  for  the  proportions  of  cement  to  aggregate  used,  1:2^:4^, 
but  in  making  the  calculations  no  account  is  taken  of  the  area  of  concrete  outside 
of  the  steel  loops  nor  of  the  strength  of  the  vertical  steel,  so  that  the  loading  is 
really  conservative. 

WALLS. 

For  the  walls  a  skeleton  structure  of  columns  and  beams  is  carried  up,  as 
shown  in  the  photographs,  and  filled  in  with  brickwork,  the  outside  face  of  the 
columns  being  veneered  with  brick  so  as  to  give  a  uniform  surface.  The  exterior 
trimmings  and  the  doors  and  window  sills  are  all  artificial  stone. 

107 


The  interior  or  partition  walls,  which  separate  the  compartments  into  which 
the  floors  are  divided,  are  of  concrete  blocks  supported  upon  reinforced  beams. 

The  concrete  blocks  were  made  of  i  part  cement  to  \V2  part  sand  to  4^ 
part  crusher  dust.  They  were  made  in  Hercules  facedown  machines  and  were 
faced  on  both  sides  during  the  process  of  the  making  with  a  layer  of  i  to  2^  mor- 
tar. The  standard  size  blocks  in  the  partition  walls  were  8  by  8  by  24  inches,  with 


fA55CN6CR  ELCVATO£ 

Fig.  47. — Detail  of  Framing  at  Elevator.     (See  p.    108.) 


two  hollow  spaces;  the  blocks  around  the  elevators  were  4  by  4  by  6  inches  solid. 
Rabbets  were  formed  in  each  end  and  in  top  and  bottom  surfaces,  and  filled  with 
cement  mortar  as  the  blocks  were  laid,  in  order  to  secure  as  perfect  a  bond  as 
possible.  No  interior  plastering  was  used  in  the  building  except  in  the  offices 
of  each  warehouse,  which  usually  occupied  only  a  small  part  of  the  first  floor. 
The  first  two  floors  of  the  building  outside  of  the  offices  were  whitewashed  by 
machines.  The  rest  was  left  without  any  finish. 

108 


STAIRS. 

Stair  details  are  shown  in  Fig.  48.  The  stairways  are  of  straight  run  from 
story,  to  story,  and  consist  of  a  slab  with  the  upper  surface  formed  into  steps. 
The  bottom  of  the  slab  is  reinforced  with  J^-inch  bars  placed  2  inches  apart,  and 
lA-'mch  rods  also  run  across  the  steps  at  occasional  intervals.  The  foot  and  head 
of  each  flight  is  specially  reinforced,  as  shown,  to  strengthen  it  at  the  ends  and 
connect  it  with  the  floor  system. 

COAL  TRESTLE. 

Reinforced  concrete  coal  trestles  are  occasionally  built,  but  comparatively  few 
designs  have  been  published,  and  the  trestle  erected  in  connection  with  this 
building  is  therefore  shown  in  considerable  detail.  Its  elevation  is  given  in  Fig. 
45  (p.  106)  and  the  details  in  Fig.  49. 


Fig.  48. — Details  of  Stairs.      (See  p.   109.) 
Two   railroad  tracks   are  carried  by  the   trestle   and   most   of  the   surface   is 
floored  over,  the  slabs  being  sloped  to  drains. 

CONSTRUCTION. 

The  warehouse  was  about  eight  months  in  building,  and   during  this  period 
11,830  cubic  yards  of  concrete  were  placed;  of  this  8,398  cubic  yards  were  rein- 
forced and  3,432  cubic  yards  plain.     The  latter  figures  included  the  blocks.     The 
mortar  finish  for  the  floors  measured  in  addition  510  cubic  yards. 
Amount  of  cement  required  was  as  follows : 

Reinforced  concrete,  10,365  barrels. 
Floor  finish,   1,690  barrels. 
Artificial  stone,  99  barrels. 
Plain  concrete,   1,770  barrels. 
Concrete    blocks,   4,051    barrels. 
Total,   17,975  barrels. 
109 


The  work  in  progress  is  shown  in  photographs,  Figs.  50  and  51.  These  were 
taken  on  the  same  date,  but  from  different  points  of  view,  the  former  from  the  rear 
of  the  building  next  to  the  railroad  track  and  the  latter  from  the  unfinished  end, 
showing  also  the  front  in  process  of  construction. 

The  concrete  was  supplied  to  the  different  parts  of  the  building  by  a  cable- 
way  which  is  clearly  seen  in  Fig.  50. 


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Fig.  49.— Details  of  Coal  Trestle.      (See  p.  109.) 

The  cable  was  supported  by  the  two  towers  located  at  each  end  of  the  build- 
ing and  far  enough  away  from  it  to  leave  room  for  the  construction  plant  between. 

The  outline  of  the  building  with  the  cableway  and  construction  plant  is 
sketched  in  Fig.  52.  The  building  rests  on  ledge,  so  that  it  was  necessary  to  ex- 
cavate a  large  quantity  of  rock,  and  the  stone  taken  out  was  utilized  in  the  con- 
crete and  also  in  the  concrete  blocks.  This  necessitated  the  installation  of  a  crush- 
ing plant,  a  somewhat  unusual  feature  in  building  construction,  but  which  was 

110 


Ill 


112 


I 
,5 

§    e 
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113 


made  possible  by  the  large  amount  of  ground  space  and  by  the  fact  that  the 
broken  stone  and  screenings  not  only  could  be  utilized  for  the  building,  but  be- 
cause there  was  a  demand  for  the  sale  of  the  surplus  coarse  material  for  railroad 
ballast. 

Crushers  were  set  to  crush  the  stone  to  maximum  size  of  il/2  inch  and  the  dust 
up  to  j4-inch  was  screened  out  for  use  in  the  concrete  blocks.  All  the  rest  of  the 
crushed  material  was  used  in  the  concrete  without  further  grading.  Sand  used  on 
the  work  was  brought  in  from  Memphis  in  cars,  while  for  the  floor  finish  the 
aggregate  was  crushed  granite. 

A  No.  4  Smith  mixer  made  the  concrete,  and  this  was  fed  with  material  by  a 
stiff-legged  derrick  having  a  65-foot  boom  and  operated  by  a  4-drum  Lambert 
engine.  The  bucket  was  of  a  i^-yard. clamshell  type,  and  dumped  the  material  into 
charging  bins  which  measured  the  materials  automatically.  The  concrete  fell  from 
the  mixer  into  buckets  which  were  taken  by  cable  and  transported  to  steel  por- 
table bins  located  on  the  floor  of  the  building  where  the  concrete  was  laid,  and 
whence  it  was  finally  delivered  by  Ransome  2-wheel  carts.  The  highest  run  of  the 
plant  was  383  cubic  yards  in  ten  hours.  A  diagram  of  the  mixing  plant  is  given 
in  Fig.  53. 

The  cableway  also  handled  lumber  for  the  forms  and  mortar  for  the  floor  fin- 
ish, which  was  put  on  as  the  concrete  was  laid. 

The  plan  of  the  plant  also  locates  the  lumber  yard  and  carpenter  shop  at  the 
other  end  of  the  building  from  the  concrete  plant.  The  forms  were  all  made  here, 
as  much  of  the  work  as  possible  being  done  by  machinery. 

The  cost  of  the  lumber  for  the  forms,  which  were  used  from  four  to  eight 
times,  was  $5,400  and  the  salvage  is  figured  at  about  20  per  cent.,  i.  e.,  it  is  es- 
timated that  the  value  of  the  lumber  left  over  which  would  be  suitable  for  another 
job  was  about  20  per  cent,  of  the  original  cost  or  about  $1,100  and  that  this  amount 
could  be  deducted  when  charging  up  the  lumber  to  this  building.  Pine  lumber 
was  used  throughout,  and  for  panels  it  was  tongued-and-grooved.  The  forms 
were  left  in  place  for  about  25  days. 

At  one  end  of  the  building  all  of  the  reinforcement  was  stored,  and  forges 
operated  by  compressed  air  from  the  signal  plant  of  the  N.  C.  &  St.  L.  Ry.  were 
so  arranged  that  they  could  be  set  at  required  points  and  the  girder  bars  which 
required  bending  thus  heated  and  bent  in  four  places  at  the  same  time.  Special 
benders  were  used  for  shaping  the  small  rods.  The  column  reinforcement  was 
assembled  and  wired  together  before  being  placed  in  the  form,  special  care  being 
taken  to  accurately  place  it.  The  cost  of  bending  and  placing  the  steel  was  0.4 
cents  per  pound. 

The  construction  gang  consisted  in  general  of  three  foremen,  3  men  mixing, 
32  men  placing,  45  carpenters,  20  steel  men,  9  enginemen,  besides  some  60  to  150 
men  on  the  excavation  and  from  10  to  40  men  on  the  stone  crushing. 

114 


77/vter  //o/>/>er 


Fig.  53. — Mixing  Plant.     (5ee  p.    114.) 


A  photograph  of  the  interior,  showing  the  columns  and  floor  system,  is  given 
in  Fig.  54. 

COST. 

The  entire  cost  of  the  building  was  about  $357,000  including  finish,  of  which 
$192,000  was  for  the  reinforced  concrete  and  the  excavation.  The  cost  of  the  con- 
struction plant,  which  is  included  in  these  sums,  was  $19,000,  an  unusually  large 
amount,  but  probably  warranted  in  this  case  by  the  size  of  the  building  and  the 
need  of  a  crusher  plant. 


117 


118 


CHAPTER  IX. 


BUSH  MODEL  FACTORY. 

The  plant  of  the  Bush  Terminal  Company,  located  in  South  Brooklyn  on  the 
east  shore  of  New  York  Bay  on  Thirty-sixth  street,  between  Second  and  Third 
avenues,  will  cover  when  completed  an  immense  area  and  comprise  some  hundred 
and  fifty  warehouses  and  factories.  Many  of  the  more  recent  of  these  buildings 
are  of  reinforced  concrete  construction,  the  factory  selected  from  this  group  for 
description  being  75  ft.  wide  by  599  ft.  long,  and  six  stories  high  above  the  base- 
ment. Several  features  of  the  design  are  of  unusual  types. 

The  Terminal  Company  owns  some  160  acres  of  land  with  nearly  three- 
quarters  of  a  mile  of  water  front.  A  number,  of  piers,. each  one-quarter  of  a  mile 
in  length,  with  wide  docks  between,  permit  the  largest  ocean  steamers  to  discharge 
and  load  without  interference.  The  large  warehouses,  50  by  150  feet,  and  from 
four  to  seven  stories  high,  provide  the  steamship  lines  renting  the  piers  with 
unusual  facilities  for  both  storage  and  trans-shipment  of  freight. 

In  addition  to  this  storage  and  shipping  business  handled  by  the  piers  and 
warehouses,  a  plan  is  already  being  carried  out  to  erect  eighteen  fireproof  factories 
or  loft  buildings,  their  floor  space  to  be  rented  for  manufacturing  purposes.  The 
first  of  these  factories,  built  in  1905,  and  the  second,  called  the  Bush  Model 
Factory  No.  2,  built  in  1906,  offer  unusually  attractive  features  because  of  the  ex- 
cellent facilities  afforded.  The  details  of  the  latter,  which  is  shown  complete  in 
Fig-  55.  from  the  subject  of  this  chapter. 

The  builder  of  this  concrete  factory  was  the  Turner  Construction  Company. 
Mr.  E.  P.  Goodrich,  formerly  chief  engineer  for  the  Bush  Terminal  Company, 
prepared  the  structural  design,  and  Mr.  William  Higginson  was  the  architect. 

DESIGN. 

Instead  of  the  usual  system  of  beams,  girders  and  slabs,  the  floors  consist 
essentially  of  heavy  girders  directly  supporting  ribbed  slabs,  designed  so  that  the 
under  surface  presents  a  corrugated  or  ribbed  appearance,  the  purpose  being  to  use 
for  the  necessarily  long  spans  a  minimum  quantity  of  concrete,  placed  most 
effectively  to  take  the  loads  upon  it. 

An  idea  of  the  general  plan  of  the  structure  is  gained  from  Fig.  56.  In 
order  to  present  it  on  a  fairly  large  scale,  only  one  end  of  the  building,  a  length 
of  about  225  feet  in  a  total  of  599  feet,  is  shown. 

The  sectional  elevation  may  be  seen  in  Fig.  57. 

Two  lines  of  columns  16  ft.  7  in.  on  centers  divide  the  factory  into  aisles  about 

119 


120 


JEL 


Fig.  57.— Sectional  Elevation  of  Bush  Factory  No.  2.      (See  f.  119-) 


24  ft.  in  width,  thus  giving  exceptionally  good  floor  space  for  either  storage  or 
manufacturing.  Heavy  girders  run  lengthwise  of  the  building  from  column  to 
column,  while  spanning  the  distance  between  these  two  lines  or  girders  and  the 
walls  is  the  ribbed  floor  system. 

Two  groups  of  four  elevators  each  are  located  one-quarter  way  from  each  end 
of  the  building,  and  in  adjoining  bays  on  each  side  of  both  groups  of  elevators  are 
the  stair  wells.  The  first  floor  plan,  Fig.  56  (p.  120),  shows  the  stairs  to  the  base- 
ment only  on  one  side  of  the  elevators,  but  an  additional  flight  is  provided  for  the 
stories  above.  Except  for  the  location  of  the  stairs,  the  floor  system  of  the  differ- 
ent stories  is  identical,  thus  simplifying  the  design  and  permitting  the  use  of  the 
same  forms  throughout. 

The  roof  is  surrounded  by  a  fire  wall  3  feet  6  inches  high.  A  series  of  sky- 
lights over  the  center  aisle  afford  additional  light  to  the  top  story. 

Round  rods  formed  into  trusses  on  the  ground  and  raised  to  place  ready  to 
drop  into  the  forms  provide  the  reinforcement.  The  proportions  of  the  concrete 
used  throughout  were  one  part  Portland  cement,  2  parts  sand,  4  parts  stone, 
being  equivalent  in  actual  volume  to  one  barrel  (4  bags)  cement,  7.2  cubic  feet  of 
sand,  and  14.4  cubic  feet  of  broken  stone.  The  aggregate  consisted  of  sand  exca- 
vated by  dredges  from  Cowe  Bay,  and  washed  gravel  of  a  size  passing  a  24-inch 
sieve. 

COLUMNS. 

The  column  footings  are  supported  by  wooden  piles,  and  the  area  of  the 
footing  is  so  large  in  proportion  to  the  size  of  the  columns  as  to  require  a  special 
design  of  heavy  horizontal  rods  and  vertical  stirrups. 

In  Factory  No.  I  the  interior  columns  are  cylindrical  and  composed  of  an 
outside  shell  of  cinder  concrete  2.1A  inches  thick.  These  cinder  concrete  cylinders 
were  prepared  in  advance  in  2-foot  lengths  in  a  zinc  mold,  with  spiral  hooping  and 
expanded  metal  forming  the  inner  surface.  After  hardening,  they  were  set  one 
upon  another  in  the  building,  and  filled  with  concrete. 

In  Factory  No.  2  the  columns  are  octagonal  in  shape,  and  composed  wholly  of 
gravel  concrete.  Just  below  the  girders  the  section  was  made  square  (see  Figs. 
56  and  57),  these  square  caps  being  of  the  same  size  on  all  the  stories  so  as  to 
avoid  altering  the  rib  and  girder  molds. 

The  columns  were  spirally  reinforced  with  round  high  carbon  steel  y%  to  l/2 
inch  in  diameter,  the  pitch  varying  in  the  different  stories.  The  loading  upon  the 
columns  was  graduated  from  500  pounds  per  square  inch  of  their  section  for  the 
upper  floor  to  1,000  pounds  per  square  inch  in  the  basement.  This,  however, 
assumed  full  loads  on  all  the  floors  at  the  same  time,  which  would  not  ordinarily 
occur,  so  that  the  columns  in  the  lower  stories  are  liable  to  be  stressed  much  less 
than  the  nominal  figures.  The  spiral  hooping  is  computed  to  assist  in  bearing 
the  load. 

122 


FLOOR  SYSTEM. 

The  general  scheme  of  design  has  been  referred  to  in  paragraphs  above. 
Longitudinal  girders  of  13  feet  4  inches  net  span,  supported  by  columns  16  feet  7 
inches  on  centers,  carry,  the  ribbed  slabs  which  run  across  the  building  with  a  net 
span  of  about  23  feet. 

The  details  of  design  of  the  beams  and  ribbed  slabs  are  drawn  in  Fig.  58.  The 
ribs  are  V-shaped  in  cross-section,  as  shown  in  Sections  aa  and  bb.  Two  i-inch 
round  rods,  one  bent  up  at  the  points  determined  by  moment  diagram,  and  the 
other  extending  horizontally  to  the  girders,  provide  for  the  tension,  and  ^-inch 
stirrups  are  bent  around  and  wired  on  to  the  horizontal  rods.  Ribs  A,  which  are 
shown  in  the  diagram,  connect  the  two  girders,  while  ribs  B,  which  run  from  the 
girders  to  each  wall,  are  similar  in  design  except  that  the  upper  rod  cannot  pro- 
ject beyond  the  support,  and  is  therefore  anchored  by  bending  it  with  a  quarter 
turn  around  another  rod  which  runs  at  right  angles  to  it  in  the  wall. 

The  steel  is  designed  for  a  maximum  pull  of  16,000  pounds  per  square  inch 
when  the  full  allowed  load  is  on  the  floor,  and  stirrups  are  provided  wherever  the 
shear  exceeds  50  pounds  per  square  inch.  The  floors  are  designed  for  a  loading 
of  200  pounds  per  square  foot  besides  the  dead  weight  of  the  concrete. 

The  design  of  the  principal  girders  is  also  shown  in  Fig.  58.  The  stirrups 
are  close  together  at  the  ends  of  the  girders  where  the  shear  is  the  greatest,  and 
each  stirrup  is  looped  around  the  tension  rods,  then  passes  up  on  each  side  of  the 
girder  and  across,  as  shown  in  the  sections.  The  stirrups  are  ^-inch  in  diameter 
near  the  end  of  the  beam,  then  at  the  points  where  the  large  rods  are  inclined  and 
thus  take  a  portion  of  the  shear,  the  size  is  reduced  to  5/16  inch,  and  this  is  con- 
tinued to  the  center  of  the  beam,  the  spacing  gradually  becoming  wider  as  the 
shear  decreases.  The  tensional  reinforcement  in  the  girders  consists  of  four 
1 54-inch  rods,  two  of  which  are  bent  up  just  beyond  the  one-quarter  points,  and  ex- 
tend nearly  to  the  center  of  the  column,  where  each  is  connected  with  the  reinforce- 
ment in  the  next  girder  by  an  oval  link  of  ^  inch  round  steel. 

In  the  bays  around  the  elevators,  the  rib  forms  were  dropped  85/2  inches,  so  as 
to  make  the  slabs  between  the  ribs  12  inches  thick,  as  shown  in  Section  CC, 
Fig.  56. 

No  reinforcement  was  placed  longitudinally  of  the  building  at  right  angles  to 
the  ribs.  In  the  floors  first  laid  with  the  V-shaped  rib,  slight  shrinkage  cracks 
occurred  between  the  ribs  and  parallel  to  them.  These,  however,  did  not  open  or 
indicate  any  structural  weakness,  and  they  were  eliminated  by  more  thorough  rod- 
ding  of  the  surface. 

The  underside  of  the  floor  construction,  and  also  the  columns,  are  shown  in 
the  photograph,  Fig.  59  (p.  126). 

The  reinforcement  was  according  to  the  Bertine  Unit  Girder  Frame  system 
as  modified  by  Mr.  Goodrich.  This  work  of  bending  and  placing  was  performed 

123 


124 


under  a  separate  contract  by  Mr.  M.  S.  Hamsley  in  an  open  shed  near  the  build- 
ing. To  the  wooden  posts  supporting  the  roof  of  the  shed,  brackets  were  fastened 
at  the  exact  locations  to  support  the  horizontal  and  the  bent-up  rods  of  the  truss. 
These  principal  members  were  bent  in  the  special  bending  machine  provided  for 
the  purpose,  then  were  brought  to  the  shed  and  hung  upon  the  brackets,  when  the 
stirrups  were  sprung  upon  them,  and  wired  to  the  large  rods  by  ordinary  stove  pipe 
wire.  The  system  of  rods  for  each  rib  or  girder  thus  formed  a  truss,  as  shown  in 
Fig.  58,  and  was  taken  by  the  general  contractors,  elevated  to  the  floor  where  it 
was  to  be  used,  and  dropped  into  the  form.  The  girder  frame  or  truss  rested 
upon  blocks  of  concrete  placed  in  the  bottom  of  the  form,  and  the  rib  truss  was 
held  upright  by  wiring  each  end  to  the  steel  in  the  girder  truss. 

On  the  girder  trusses,  four  men  worked  in  a  gang,  and  could  put  together, 
after  the  large  rods  were  bent,  from  twenty-five  to  thirty  frames  per  day. 

The  spirals  for  the  column  reinforcement  in  Factory  No.  I  were  formed 
around  a  horizontal  skeleton  drum  by  two  men  who  wound  the  J4-inch  wire 
around  it  and  wired  it  to  the  54-inch  longitudinal  rods.  In  Factory  No.  2  a 
special  machine  was  used  for  bending. 

WALLS. 

The  walls  consist  essentially  of  glass  between  concrete  columns.  The  window 
lintels  are  reinforced  concrete  beams  and  above  the  floor  level  8-inch  walls  were 
carried  up  from  the  floor  to  the  window  sills,  which  formed  a  part  of  the  wall  and 
were  troweled  hard  while  setting.  These  low  walls  were  put  in  after  the  structural 
part  of  the  concrete  was  several  stories  above  them,  as  shown  in  Fig  60,  page  128. 

The  building  is  without  partitions  except  around  the  elevator  and  stair  wells. 
These  were  built  after  the  floors  were  completed,  and  instead  of  being  located 
directly  under  the  beams  or  ribs  they  were  placed  alongside  of  them,  slots  being 
left  in  the  floor  slab  so  that  they  could  be  poured  from  the  floor  above  directly 
into  the  forms  built  for  them.  The  reinforcement  of  these  partition  walls  consists 
of  ^6-inch  round  rods  15  inches  apart  both  horizontally  and  vertically. 

The  exterior  columns  are  divided  into  blocks  by  horizontal  moldings  attached 
to  the  inside  of  the  form.  After  completing  the  building,  the  walls  were  given  a 
wash  of  Lafarge  cement. 

CONSTRUCTION. 

Two  mixing  plants  were  located  in  the  basement  of  the  building  near  the  two 
elevator  shafts.  The  arrangement  of  the  entire  plant  was  according  to  the  Ran- 
some  design.  Each  mixer  was  located  on  a  platform  about  3  feet  above  the  floor 
level,  and  the  raw  material  supplied  to  it  by  wheelbarrows.  An  electric  motor 
supplied  the  power.  The  hoist,  driven  by  a  separate  motor,  received  the  con- 
crete directly  from  the  mixer,  and  raising  it  to  the  floor  where  the  concrete  was 
being  laid,  dumped  it  into  a  hopper,  from  which  it  was  fed  by  a  gate  into  2-wheel 

125 


126 


carts  and  conveyed  to  place.  Each  construction  plant  cost  in  the  neighborhood 
of  $2,500. 

The  building  was  completed  in  seventy-four  working  days,  the  average  prog- 
ress being  10.4  days  per  story.  During  this  time  16,000  cubic  yards  of  concrete 
were  placed  and  950  tons  of  steel.  The  usual  gang  consisted  of  80  carpenters  and 
180  laborers. 

Fig.  60  illustrates  the  work  in  progress  on  the  fifth  floor,  where  the  column 
and  girder  forms  are  also  being  set  for  the  floor  above.  The  forms  and  braces 
are  removed  from  the  first,  second  and  third  floors,  and  they  are  being  raised  from 
the  fourth  floor  to  the  floor  above  by  falls  carried  by  a  triangular  frame,  which 
is  seen  projecting  above  the  work.  The  photograph  also  shows  the  bracing  and 


Fig.   61. — View   Illustrating  Form   Construction   for   Bush   Terminal   Factory.      (See 


alignment  of  the  faces  of  the  exterior  column  forms.  On  the  second  floor  the 
panels  below  the  windows  are  being  poured,  a  part  of  the  forms  being  still  in  place. 
From  the  panel  next  to  the  corner  and  also  from  the  panels  of  the  first  story  the 
forms  have  been  removed  and  show  the  finished  surface.  The  molding  of  the 
columns  also  distinctly  appears. 

The  photograph,  Fig.  61,  shows  the  general  layout  of  the  forms,  the  girder 
forms  extending  lengthwise  of  the  view  with  the  ribs  at  right  angles  to  them.  The 
rib  forms,  which  are  approximately  triangular,  rest  directly  upon  the  sides  of  the 
girder  molds,  and  narrow  pieces  of  plank  are  dropped  between  them  to  form  the 
bottom  of  the  rib. 

127 


128 


The  total  cost  of  the  building  complete  was  approximately  $450,000.  It  has 
automatic  sprinklers,  steam  heat,  ample  toilet  rooms,  heavy  freight  elevators, 
wire  glass  windows  in  metal  frames,  standard  automatic  fire  doors,  hard  wood 
floors,  and  so  forth,  to  make  really  a  model  factory. 


129 


130 


CHAPTER  X. 


PACKARD  MOTOR  CAR  FACTORY. 

The  Packard  Motor  Car  Company  at  Detroit,  Michigan,  turned  out  in  1905 
700  automobiles.  The  demand  for  these  cars  necessitated  an  enlargement  of  the 
plant,  and  in  the  spring  of  1906,  after  careful  consideration  of  the  various  types  of 
construction,  it  was  decided  to  build  the  new  factory  of  reinforced  concrete.  The 
building  illustrated  on  the  opposite  page  is  the  result. 

Plans  were  drawn  at  once  by  Mr.  Albert  Kahn,  architect,  and  the  contract  was 
let  to  the  Concrete  Steel  and  Tile  Construction  Company,  of  Detroit,  the  Trussed 
Concrete  Steel  Company  acting  as  engineers. 

The  structure,  as  is  shown  on  the  plans,  is  long  and  narrow,  and  in  the  form 
of  an  L,  so  that  all  parts  of  the  floor  are  well  lighted.  It  is  proposed  at  some 
future  time  to  extend  the  building  by  carrying  out  another  wing.  At  present  there 
are  two  stories,  and  the  roof  is  designed  as  a  floor  with  a  temporary  covering, 
as  described  below,  so  that  another  story  can  be  added  at  a  later  date.  The  first 
floor  is  laid  upon  the  ground  with  no  basement. 

The  building  is  designed  to  provide  very  large  floor  area  without  interference 
of  columns.  A  single  row  of  columns  runs  through  the  center  of  the  factory,  and 
these  are  32  feet  apart  on  centers,  a  distance  slightly  greater  than  the  space  be- 
tween the  line  of  columns  and  the  walls  on  each  side. 

Although  a  motor  car  appears  to  be  a  heavy  machine  in  itself,  the  parts  are 
comparatively  light,  and  by  placing  the  heavier  machinery  on  the  ground  floor, 
it  was  possible  to  allow  a  floor  load  of  only  100  pounds  per  square  foot,  in  addi- 
tion to  the  dead  load  or  weight  of  the  structure  itself.  In  certain  parts  of  the 
floor,  this  load  is  increased,  around  the  elevators  especial  care  being  taken  to  give 
an  excess  of  strength.  This  comparatively  light  live  load  together  with  the  type 
of  floor  construction  selected,  a  combination  of  tile  and  concrete,  permitted  the 
rather  unusually  long  spans. 

The  general  plan,  Fig.  63,  shows  the  layout  of  the  floor,  with  an  outline  of 
the  location  of  the  beams,  girders  and  columns. 

Fig.  64  presents  elevations  and  sections  taken  lengthwise  of  the  building,  and 
also,  at  the  right,  a  typical  or  transverse  section. 

FLOOR  SYSTEM. 

The  first  floor  is  built  directly  upon  the  ground.  The  top  soil  was  removed 
and  the  surface  thoroughly  tamped,  then  covered  with  6  inches  of  cinders  rammed 

131 


133 


hard  to  receive  the  concrete.  On  top  of  this  porous  layer,  a  5-inch  thickness  of 
concrete  in  proportions  I  part  cement  to  2  parts  sand  to  5  parts  broken  limestone 
was  spread,  and  covered  with  a  i-inch  mortar  surface,  laid  before  the  concrete 
below  had  set,  in  proportions  2  parts  cement  to  3  parts  sand,  and  thoroughly 
troweled  with  a  steel  trowel  to  a  smooth  surface.  This  was  divided  into  sections 
as  it  was  being  laid  to  provide  contraction  joints. 

In  the  floor  above,  the  wide  spacing  of  the  columns,  already  mentioned,  neces- 
sitated beams  and  girders  of  unusual  length,  and  consequently  of  unusual  width 
and  depth.  -The  girders  (see  Fig.  63)  are  30  feet  8  inches  in  net  length  between 
columns,  or  32  feet  8  inches  on  centers,  and  measure  22  inches  wide  by  36  inches 
deep  from  top  of  slab.  Each  girder  supports  one  beam  at  the  center  of  its  span, 
the  alternate  beams  running  directly  into  the  columns.  The  reinforcement,  which 
consists  of  Kahn  trussed  bars*,  is  very  clearly  seen  in  section  NN  in  the  figure. 
The  girder  selected,  as  shown  on  the  plan  below  it,  is  taken  at  the  intersection  of 
the  two  wings  of  the  building,  and  the  column  at  the  right  is  therefore  narrower 
than  the  left-hand  support,  the  latter  illustrating  the  typical  columns  in  the  build- 
ing. 

The  floor  system,  as  already  mentioned,  is  designed  for  a  load  of  100  pounds 
per  square  foot  in  addition  to  the  weight  of  the  concrete  and  steel.  The  design 
is  figured  so  that  this  loading  will  not  produce  a  tension  in  the  steel  exceeding 
16,000  pounds  per  square  inch,  and  will  keep  the  compression  in  the  concrete 
everywhere  within  the  limit  of  500  pounds  per  square  inch.f  The  proportions  of 
the  concrete  are  one  part  Atlas  Portland  cement,  2  parts  sand,  4  parts  broken  lime- 
stone, the  exact  measurements  being  one  barrel  (4  bags)  cement  to  7.56  cubic  feet 
sand  to  15.10  cubic  feet  stone. 

The  shear  or  diagonal  tension  is  provided  for  by  bending  some  of  the  tension 
rods  and  also  by  the  bent-up  portion  of  the  individual  bars. 

The  beams,  of  which  a  typical  section,  MM,  is  also  shown  in  Fig.  63,  are  27 
feet  I  inch  net  span  between  girder  and  wall  column.  The  general  construction 
is  similar  to  the  girder  shown  above  it  and  labeled  beam  "B"  except  that  fewer 
bars  are  bent  up  because  the  shear  is  less.  The  section  of  the  typical  beams  is  30 
inches  deep  and  18  inches  in  width. 

A  somewhat  peculiar  slab  section  is  shown  in  the  upper  portion  of  section 
MM.  This  is  made  up  of  sections  of  tile  and  concrete  placed  alternately.  The  floor 
slab  is  14  feet  6  inches  net  span  between  beams,  and  consists  essentially  of  a  series 
of  concrete  beams  8  inches  deep  by  4  inches  in  width  spaced  16  inches  apart  on 
centers  and  reinforced  with  Kahn  trussed  bars.  These  little  beams  run  directly 
into  the  upper  surface  of  the  regular  beams,  labeled  "A"  on  the  plan,  and  are  sup- 
ported by  them. 

*  See  Illustration,  Fig.  ,07,  page  183. 

t  Figured  by  the  parabolic  formula,  or  nearly  600  pounds  by  the  straight-line  formula. 

134 


Between  these  little  beams  hollow  tile  is  laid,  the  method  of  construction  be- 
ing to  first  place  the  tile  upon  the  level  panel  form,  then  set  the  reinforcing  metal 
in  position  between  the  rows  of  tile,  and  pour  the  concrete.  The  object  of  the 
insertion  of  tile  is  to  lighten  the  floor  slab,  and  thus  reduce  the  weight  upon  the 
beams  and  girders  by  occupying  space  which  must  otherwise  be  solid  concrete. 
It  also  permits  very  simple  form  construction,  consisting  chiefly  of  a  large  plain 
surface  readily  built  and  removed. 

After  hardening,  the  under  surfaces  of  the  floors  are  plastered  with  2  inches  of 
Portland  cement  mortar  to  hide  the  tile  and  form  the  ceiling.  On  top  of  the  floor 
slab,  a  2-inch  wearing  surface  of  cement  mortar  finish  is  also  laid  to  make  the 
finished  floor. 


Fig.  65. — Typical  Interior  Columns  in  Packard  Factory.      (See  p.  136.) 

The  beams  around  the  elevators  are  especially  constructed  to  sustain  a  weight 
of  8,000  pounds  live  or  superimposed  load,  plus  8,000  pounds  from  the  counter- 
weights, plus  4,000  pounds,  the  weight  of  the  elevators  loaded. 

The  original  specifications  called  for  a  roofing  designed  to  carry  40  pounds  per 
square  foot,  but  it  was  afterwards  decided  to  build  this  as  a  floor  of  the  same  con- 
struction as  the  second  floor,  so  that  another  story  could  be  added  when  required. 

135 


On  top  of  the  level  surface  thus  formed,  a  layer  of  cinders  was  spread  and  shaped 
so  as  to  pitch  to  sumps;  a  i-inch  layer  of  mortar  was  laid  on  the  cinders,  and  upon 

COLUMNS. 

The  interior  columns  are  in  general  24  inches  square  and  designed  for  a  safe 
loading  which  produces  a  compressive  stress  in  them  not  exceeding  450  pounds 
per  square  inch.  The  concrete  was  made  in  proportions  one  part  Portland  cement 
to  il/2  parts  sand  to  2  parts  stone,  and  reinforced  with  Kahn  trussed  bars,  as  in- 
dicated in  Fig.  65  (p.  135). 

The  wall  columns  are  similar  in  design,  but  smaller  in  section  and  spaced  16 
feet  4  inches  apart  on  centers,  so  that  all  the  cross  beams  run  directly  into  them. 
A  longitudinal  beam  at  each  floor  line  connects  these  wall  columns  and  also  sup- 
ports the  brickwork,  which  is  built  up  to  the  level  of  the  window  sills. 


\ 


Fig.  66. — Stair  Details.     (See  p.    138.) 
136 


STAIRS. 

The  stair  details  may  be  seen  in  Fig.  66  (p.  136).  They  consist  in  general  of  a 
slab  reinforced  with  Kahn  trussed  bars  and  surface,  with  a  i-inch  tread  of  cement 
mortar. 

A  photograph  of  the  stairs,  Fig.  67  (p.  137),  taken  soon  after  the  concrete  was 
laid,  very  clearly  illustrates  their  arrangement  and  design. 

CONSTRUCTION. 

The  factory  was  sixteen  weeks  in  building,  and  in  its  construction  2,100  cubic 
yards  of  concrete  were  laid  and  225  tons  of  steel  placed. 

The  arrangement  of  the  plant  is  clearly  shown  in  Fig.  68.     Two  mixing  plants 


Fig.  68. — Plan  of  Construction  Plant.     (See  p.   138.) 

were  located  as  shown,  one  with  a  Ransome  mixer  fed  by  an  automatic  hoist,  and 
one  with  a  Smith  mixer.  Each  of  the  mixers  dumped  into  a  bucket  hoist,  which 
elevated  the  concrete  to  a  bin  on  the  fourth  floor,  where  it  was  placed  by  wheel- 
barrows. The  work  of  construction  is  shown  in  the  photograph  in  Fig.  69.  One 
of  the  concrete  hoists  is  seen  on  the  left,  and  one  of  the  double  platform  hoists 
which  elevate  the  tile  and  steel  is  on  the  right.  The  upper  surface  of  the  floor 
slabs,  with  the  alternating  concrete  and  tile,  and  the  top  surface  of  the  girders  and 
beams  are  also  distinctly  visible  in  the  foreground.  The  underside  of  the  floor, 
with  the  alternate  tile  and  concrete  surface,  is  illustrated  in  Fig.  70,  and  the  in- 
terior of  the  finished  buildings  is  presented  in  Fig.  74  (p.  145). 

FORMS. 

For  the  forms,  1 24-inch  lumber  was  used,  except  that  for  the  floor  panels  No. 
I  Norway  pine,  dressed  four  sides,  was  employed.  The  cost  of  lumber  averaged 
$27  per  thousand,  but  there  was  a  large  salvage,  that  is,  a  large  proportion  of  the 
lumber  was  suitable  for  use  on  another  job,  because  of  the  wide  floor  slabs  and 
large  beams  and  girders,  which  cut  up  the  stock  less  than  usual. 

Typical  form  details  are  drawn  in  Fig.  71  (p.  141).  The  clamps  or  brackets  of 

138 


139 


140 


%y 


•: 


1 


1 


1 


J 


9^3'   ~PK 
141 


the  column  forms  are  driven  up  with  wedges  so  as  to  make  tight  and  prevent  twist- 
ing. The  beam  molds  on  the  right  of  the  diagram  are  held  together  with  iron 
clamps  or  braces  placed  against  2  by  4  inch  battens,  which  also  serve  as  supports 
for  the  joists  which  carry  the  sheathing. 

The  centering  was  erected  so  that  the  column  forms  could  be  removed  first, 
then  the  sides  of  the  beam  molds,  and  next  the  floor  forms,  leaving  the  bottom  of 
the  beam  molds  with  the  .shores  in  place.  These  shores  were  generally  left  in  three 
or  four  weeks,  while  the  remainder  of  the  forms  were  taken  down  in  two  or  three 
weeks.  Owing  to  the  length  of  the  span  and  the  heavy  weight  of  the  beam  molds, 
the  bottoms  of  these  were  built  on  the  ground  and  then  raised  to  place,  and  the 
sides  were  constructed  in  position.  This  avoided  the  elevating  of  the  completed 
mold. 

Fig.  72  shows  the  exterior  of  the  building  under  construction,  with  the  column 
and  beam  forms  and  the  struts  still  in  place  in  the  second  story.  Some  of  the  first 
floor  shores  also  remain  to  support  the  principal  beams  and  girders.  The  illus- 
tration also  shows  the  platform  hoist  for  raising  the  tile. 

The  photograph  in  Fig.  73  was  taken  a  little  later,  and  shows  the  structural 
portion  of  the  building  practically  completed  but  with  some  of  the  shores  and  part 
of  the  centering  still  in  place  on  the  upper  floor.  The  window  frames  are  set 
along  one  side  of  the  first  story  and  the  brickwork  laid  there.  In  the  background 
can  be  seen  the  stair  and  elevator  well  and  just  in  front  of  it  the  concrete  hoist. 

The  exterior  view  of  the  completed  factory  is  shown  in  the  photograph,  Fig. 
62,  page  130. 


142 


143 


144 


145 


146 


CHAPTER  XL 


TEXTILE  MACHINE  WORKS. 

An  unusual  type  of  factory  building  was  erected  at  Reading,  Penn.,  by  the 
Textile  Machine  Works  during  the  winter  of  1904-5  for  the  manufacture  of  ma- 
chinery for  cotton  and  woolen  mills.  Comparatively  light,  but  high  speed,  ma- 
chine tools  were  installed,  such  as  lathes,  planers  and  drills. 

The  feature  of  most  interest  in  the  design  is  the  floor  system.  The  columns 
were  built  in  place  in  the  usual  way  by  pouring  concrete  into  wooden  molds,  but, 
instead  of  building  wooden  forms  in  place  for  the  floor  system  and  pouring  the 
concrete  into  them,  all  the  members  were  molded  separately  and  placed  after 
hardening.  The  design  of  the  beams  and  girders  also  was  decidedly  unusual,  for 
to  reduce  their  weight  and  the  quantity  of  concrete  in  them,  the  Visintini  system 
was  adopted,  in  which  the  members  are  of  open  or  lattice  work,  formed  as  actual 
trusses. 

The  Visintini  system  was  invented  by  Franz  Visintini,  an  architect  of  Zurich, 
Switzerland.  Although  applied  in  a  number  of  cases  in  Europe,  this  building  was 
its  first  introduction  into  the  United  States. 

The  Concrete-Steel  Engineering  Company,  of  New  York,  who  controls  the 
American  patents,  designed  the  building  and  also  acted  as  consulting  engineers 
during  erection.  Day  labor  was  employed  in  the  Construction,  the  men  being 
directly  upon  the  pay  roll  of  the  Textile  Machine  Works. 

The  building,  which  is  shown  complete  in  Fig.  75,  is  50  feet  wide  by  200  feet 
long  and  four  stories  high.  Wall  columns  are  spaced  i2l/2  feet  apart,  and  a  center 
line  of  columns  on  the  same  spacing  extends  through  the  center  of  the  building. 
The  principal  girders,  24  feet  long,  run  across  the  building,  connecting  the  wall 
and  center  columns. 

COLUMNS. 

The  column  footings  are  not  reinforced  but  are  stepped  as  shown  in  Fig.  76, 
and  laid  in  proportions  1 13 :6.  To  assist  in  transmitting  the  pressure  of  the 
columns,  which  are  of  richer  proportions,  i  :2  -.4,  and  also  to  afford  a  bearing  for 
the  column  rods,  a  ^-inch  plate  was  set  3  inches  below  the  top  of  the  footing. 
After  laying  the  footings,  the  column  reinforcement  was  placed  with  the  longitudi- 
nal rods  butting  directly  upon  the  plate,  as  shown,  and  forms  of  dressed  white  pine 
were  built  around  them.  The  concrete  of  the  column  was  then  poured  in  the 

147 


P/0*. 


A?  ft?  F-/6  a/xt '  L-3  to  L-/J 

Fig.  76.— Details  of  Columns  in  Textile  Machine  Shop  (See  Fig.  78).    (See  p.  147-) 

148 


149 


:J 


150 


usual  manner.  The  details  of  a  typical  interior  and  exterior  column  are  shown  in 
Fig.  76,  and  in  Fig.  77  (p.  149)  the  columns  are  illustrated  as  they  appeared  with  the 
shoulders  for  receiving  the  girders  and  with  the  rods  projecting  upwards  so  as  to 
join  on  the  columns  in  the  next  story  above.  The  center  columns  in  the  lower 
story  are  18x18  inches  square  and  15x15  inches  for  those  above.  Wall  columns 
are  15x15  inches  on  the  first  floor  and  12x15  inches  above.  The  principal  rein- 
forcement in  the  columns  through  the  middle  of  the  building  consists  of  four 
i%-\nch  vertical  rods  in  the  two  lower  stories,  and  four  i-inch  rods  in  the  third 
and  fourth  stories.  Three  half-inch  Thacher  rods*  are  also  inserted  in  the  ex- 
terior columns.  Occasional  loops  of  small  rods  hold  the  heavier  rods  in  place, 
and  assist  in  resisting  shear.  The  ends  of  the  principal  rods  are  planed  smooth  and 
they  are  butted  and  connected  with  a  6-inch  length  of  pipe  sleeve,  so  that  perfect 
compression  is  assured.  The  outside  rows  of  columns  are  similar  except  that  the 
rods  are  differently  spaced.  The  pressure  on  the  concrete  is  limited  to  350  pounds 
per  square  inch. 

FLOOR  SYSTEM. 

Foundation,  floor  and  roof  plans,  and  sketches  of  column  footings  are  drawn 
in  Fig.  78. 

Running  across  the  building  from  column  to  column  and  12^2  feet  apart  on 
centers  are  the  large  Visintini  lattice  girders  24  feet  long. 

In  ordinary  design  these  would  be  connected  by  floor  beams  spaced  6  or  8  feet 
apart,  with  slabs  between  the  beams.  The  Visintini  system,  however,  permits  the 
slabs  and  floor  beams  to  be  laid  as  one;  that  is,  after  placing  the  girders  the  floor 
beams  were  laid  from  girder  to  girder  but  close  together  so  as  to  form  a  floor 
slab  of  themselves.  For  a  wearing  surface,  a  maple  floor  was  laid  upon  2  by 
4-inch  stringers,  which  were  bolted  together  at  the  ends  so  as  to  tie  the  floor  to- 
gether lengthwise  of  the  building  as  well  as  to  form  nailing  strips.  Cinder  con- 
crete was  placed  between  the  strips. 

The  details  of  a  typical  floor  girder,  roof  girder  and  floor  beam  are  shown  in 
Fig.  79.  The  girders  are  shaped  like  a  Pratt  truss,  a  common  type  used  in  steel 
bridges,  and  the  computations  of  stresses  were  made  as  in  bridge  design.  The 
bottom  chord  consists  of  a  slab  of  concrete  reinforced  with  3  round  rods  to  take 
all  of  the  tension,  and  the  top  chord  in  compression,  is  similarly  reinforced.  The 
vertical  web  members,  which  are  in  compression,  are  of  plain  concrete,  while  the 
diagonals  are  each  reinforced  for  tension  with  rods,  whose  ends  are  attached  to 
the  rods  of  the  top  and  bottom  chords. 

The  floor  beams  are  only  6  inches  thick  and  12  feet  5  inches  long,  and  these,  as 
stated  above,  also  form  the  slab,  being  placed  close  together.  They  are  designed  and 


See  illustration,  Fig.  102,  page  179. 

151 


il- 


152 


154 


computed  like  a  Warren  truss  with  all  of  the  web  members  inclined  at  45°,  half  of 
them  in  tension  and  half  in  compression. 

One  of  the  chief  advantages  of  this  type  of  construction  already  noted,  is  in 
the  method  of  molding  the  beams  and  girders  so  as  to  reduce  the  cost  of  forms. 
In  this  case  the  work  was  greatly  facilitated  because  the  building  was  erected  in 
winter.  The  beams,  of  which  there  are  about  2,900,  were  molded  on  the  ground  in 
an  adjacent  building,  as  shown  in  Fig.  80  (p.  153).  At  the  left  of  the  photograph  is 
the  bottom  board  of  the  forms,  to  which  are  screwed  triangular  cast  iron  plates. 
These  locate  the  triangular  cores  which  were  set  upon  them.  Two  boards  formed 
the  sides  of  the  mold,  and  when  these  were  set  and  clamped,  the  reinforcement 
previously  bent  to  shape  and  formed  into  three  trusses,  was  carefully  placed.  The 
soft  concrete  was  then  poured  in  and  lightly  tamped.  The  proportions  for  the 
beam  concrete,  based  on  cement  loosely  measured,  were  one  part  Portland 
cement  to  one  part  sand  to  three  parts  stone  screenings.  The  floor  beams  weigh 
only  480  pounds  each. 

The  cores,  which  were  oiled  before  placing,  were  pulled  a  few  hours  after 
pouring,  and  the  side  and  bottom  forms  were  left  on  for  two  days,  when  the  beams 
were  hard  enough  to  move.  After  setting  about  10  to  30  days  longer,  as  needed, 
they  were  carried  to  the  building  and  raised  to  place.  They  were  run  on  to  the 
first  floor  of  the  building,  and  then  raised  through  an  open  bay  to  the  floor  where 
they  were  required  by  a  platform  elevator.  A  view  of  girders  in  place  and  of  a 
floor  beam  on  the  elevator  is  shown  in  Fig.  81. 

Two  of  the  floor  beams  were  tested  to  destruction  and  broke  under  a  load  of 
pig  iron  weighing  342  pounds  per  square  foot.  The  building  is  designed  for  a 
safe  working  load  of  75  pounds  per  square  foot. 

The  girders  weigh  about  three  tons  each,  and  were  molded  upon  the  floor  im- 
mediately underneath  their  final  position,  so  that  they  required  only  to  be  hoisted 
into  place,  a  distance  of  14  feet,  which  was  done  by  means  of  a  special  derrick  and 
two  strong  hoists. 

The  proportions  were  one  part  Portland  cement  (measured  loosely),  i^  parts 
sand,  and  3TA  parts  broken  trap  rock  passing  a  i^-inch  ring. 

To  tie  the  columns  together  across  the  building,  the  floor  beams  were  placed 
with  a  S-inch  opening  between  their  ends,  and  this  space  filled  with  concrete  in 
which  was  imbedded  a  rod,  as  shown  just  above  the  cross-section  of  the  girder 
in  the  lower  portion  of  Fig.  79.  The  method  of  placing  the  floor  beams  is  illus- 
trated in  Fig.  77.  They  are  laid  on  top  of  the  girders  and  are  so  thin  that  they 
appear  in  the  photograph  like  planks,  but  careful  inspection  of  the  beams  at  the 
right  of  the  photograph,  which  have  just  been  placed,  will  show  their  lattice 
formation. 

Another  view  of  the  building  under  construction  is  shown  in  Fig.  82  (p.  157). 

155 


COST. 

The  total  cost  of  the  building  was  about  $40,000  divided  as  follows : 

Concrete    materials 5,961.66 

Iron  and  steel 6,277.46 

93,000  feet  B.   M.  lumber 2,514.61 

Excavating    388.23 

Foundry  work    (casting  for  cores) 642.20 

Machine  shop  work  (making  all  forms) 3,295.21 

Carpenter    work -. 4,971-83 

Labor  molding  and  pouring  concrete 7,919.27 

Labor  placing  concrete  beams. 586.35 

Labor  (outside  of  concrete  work  proper) 2,422.25 

Brick  walls,  wooden  floors  and  trim 4,000.00 


Total    $38,979-07 

This  sum  does  not  include  the  cost  of  engineering  nor  of  general  expense. 
About  178  tons  of  steel  were  used  in  the  reinforcing  and  the  cost  of  bending 
and   placing   it   was   about    1A   cent   per   pound ;    3,590   barrels    of   Atlas    Portland 
cement  were  used,  1,400  tons  of  stone  and  1,495  tons  of  sand. 

The  total  cost  of  the  completed  building  including  the  finish  was  7.7  cents  per 
cubic  foot. 


156 


157 


CHAPTER  XII. 


FORBES  COLD  STORAGE  WAREHOUSE. 

Reinforced  concrete  is  admirably  adapted  to  the  construction  of  cold  storage 
warehouses  because  of  the  advantages  from  a  sanitary  standpoint.  A  monolithic 
floor  construction,  free  from  structural  joints  and  seams,  fireproof,  waterproof,  and 
practically  vermin  proof,  is  unquestionably  an  ideal  floor  construction  for  this 
type  of  building.  These  advantages,  together  with  the  small  cost  of  maintenance 
and  favorable  insurance  rates,  led  to  its  selection  by  Mr.  W.  S.  Forbes  as  the 
structural  material  for  the  cold  storage  warehouse  and  abattoir  at  Richmond,  Va. 

The  bids  for  the  construction  indicated  that  it  would  cost  about  10  per  cent, 
more  to  build  of  reinforced  concrete  with  brick  walls  than  to  carry  out  the  design 
in  wood,  but  the  owner  was  convinced  that  the  more  serviceable  and  satisfactory 
results  attained  with  the  concrete  outweighed  the  slight  increase  in  cost.  As  a 
result,  this  building  is  one  of  the  most  thoroughly  equipped  cold  storage  plants 
and  slaughter  houses  in  the  country. 

The  plant  was  erected  by  Mr.  Walter  P.  Veitch,  general  contractor,  from 
plans  of  Messrs.  Wilder  and  Davis,  of  Chicago,  packing  house  experts.  The  rein- 
forced concrete  work  and  structural  features  of  the  building  were  designed  by  the 
General  Fireproofing  Company,  of  Youngstown,  O.,  who  supplied  the  steel  rein- 
forcement for  the  building  and  superintended  its  installation.  The  structure  is 
160  feet  7  inches  long,  85  feet  g%  inches  wide  at  one  end,  diminishing  to  a  width 
of  79  feet  at  the  other  end.  A  part  of  the  building  is  six  stories  high  with  a  base- 
ment in  addition,  the  remaining  portion  having  four  stories  and  basement. 

The  two  lower  stones  are  utilized  for  cold  storage  purposes,  and  are  insulated 
from  the  outside  and  from  the  floors  above  by  10  inches  of  cork  insulation  on  top 
of  the  concrete  floor. 

The  two  lower  floors  are  finished  with  i-inch  granolithic.  This  enables  the 
floors  to  be  kept  clean  and  sanitary  by  flushing  with  the  hose  and  scrubbing, 
gutters  leading  to  drains  being  provided  to  collect  the  drip  or  scraps,  and  the 
refuse  from  the  meats  and  their  by-products. 

The  third  story  is  the  shipping  floor,  and  its  ceiling  is  completely  equipped 
with  a  system  of  trolleys  hanging  from  specially  designed  hangers  suspended  from 
the  concrete  beams. 

The  fourth  floor  is  used  as  an  office  and  general  salesroom,  and  this  floor  is 
so  insulated  from  above  and  below  as  to  maintain  a  uniform  temperature. 

158 


A  portion  of  the  fifth  floor  is  devoted  to  ice  storage,  and  the  remainder  is 
occupied  by  the  hanging  room,  hog  cooler  department,  and  brine  chambers. 
Above  this  floor,  under  the  roof,  is  a  thoroughly  insulated  air  space. 

The  meats  and  other  products  are  transferred  from  one  story  to  another  by 
means  of  large  eleVators  in  shafts  whose  walls  are  insulated  with  cork. 

The  live  loads  on  the  different  floors  vary  from  250  to  400  pounds  per  square 
foot,  the  heavier  loads  occurring  mostly  on  the  fifth,  where  salt  and  general  mer- 
chandise tubs  of  lard  and  barrels  of  pork  are  stored  for  sale. 

DETAILS  OF  CONSTRUCTION. 

The  general  plan  of  the  warehouse  is  shown  in  Fig.  83  (p.  159),  the  cross  sec- 
tion in  Fig.  84,  the  longitudinal  section  in  Fig.  85,  and  the  south  elevation  in  Fig. 
86. 

The  first  and  second  stories,  that  is,  the  basement  and  sub-basement,  are 
below  grade,  and  surrounded  by  heavy  concrete  foundation  retaining  walls.  From 


Pig.  84. — Cross-Section  of  Forbes  Cold  Storage  Warehouse. 

the  street  grade  the  exterior  walls  are  brick,  varying  in  thickness  from  20  inches 
above  the  foundation  to  13  inches  at  the  top.  Bearing  walls,  although  more  ex- 
pensive, were  selected  in  preference  to  skeleton  construction  with  curtain  walls 
to  provide  more  complete  insulation. 

The  interior  columns  are  of  concrete,  reinforced  with  four  vertical  rods,  vary- 
ing from  i  inch  to  34  inch  in  the  different  stories,  and  tied  at  intervals  of  about 
12  inches  with  wire  ties.  The  columns  are  located  16  feet  apart  in  one  direction 
and  20  feet  apart  in  the  other. 

160 


164 


The  girders  run  across  the  building  on  the  i6-foot  span,  with  beams  at  right 
angles  to  them  spanning  from  column  to  column,  and  also  through  the  central 
points  of  the  girders,  thus  making  the  bays  20  feet  by  8  feet. 

The  beams  and  girders  are  of  the  same  depth  throughout  the  building,  namely 
24  inches,  with  a  view  to  facilitating  the  installation  and  operation  of  the  trolley 
systems.  The  floor  slabs  and  the  roof  slabs,  which  are  reinforced  with  expanded 
metal,  are  4^  inches  and  3^  inches  respectively. 

An  interior  view  of  one  of  the  floors  after  completing  the  concreting  is  given 
in  Fig.  87  (p.  163). 

GIRDER  FRAMES. 

The  details  of  the  reinforcement  in  the  beams  and  girders  are  shown  in  Fig.  88 
(p.  164),  with  the  typical  sizes  of  steel  for  a  floor  carrying  250  pounds  per  square 
foot  in  addition  to  the  weight  of  the  concrete. 


Fig. 


-Placing  of  Pin-Connected  Girder  Frames.       (See  p.   167.) 


Each  frame  is  a  complete  truss  of  the  pin-connected  girder  system,  two  or 
more  frames  constituting  the  reinforcement  for  each  beam  and  girder.  At  inter- 
sections the  frames  are  connected  by  steel  links  and  bolts,  thus  providing  con- 
tinuous ties  across  the  building  in  both  directions. 

The  frames  were  designed  for  the  special  floor  loads  and  fabricated  in  the  shop 
of  the  General  Fireproofing  Company  at  Youngstown,  Ohio,  then  shipped  to  the 

165 


pi   rp    rp'efi    rig  tan    an    an   in  m  * 


m 


SucnoN  THROUGH  GIRDERS 
Fir.  90.— Details  of  Form  Construction.      (See  p.  167.) 

166 


T 


building  ready  for  installation  in  the  forms.  The  tension  and  shear  members  are 
held  rigidly  in  place  by  steel  collars  and  pneumatically  driven  steel  wedges,  so  that 
the  displacing  of  the  reinforcement  by  careless  workmanship  is  impossible.  The 
placing  of  the  reinforcement  is  illustrated  in  Fig.  89  (p.  165). 

FORMS. 

Isometric  views  of  sections  of  the  forms  are  illustrated  in  Fig.  90.  The  form 
lumber  was  Virginia  pine,  planed  three  sides,  or  else  tongue-and-grooved,  and 
cost  $20  per  thousand.  The  form  construction  was  simplified  by  the  uniform 
depth  of  the  beams  and  girders,  each  of  them  being  24  inches  deep,  measured  from 
top  of  the  slab.  The  forms  were  left  in  place  from  two  to  three  weeks,  being  used 
on  the  average  three  times. 

CONSTRUCTION  PLANT. 

The  construction  plant  consisted  of  a  Smith  mixer  with  elevator  for  hoisting 
the  concrete  in  wheelbarrows,  from  which  it  was  dumped  into  place.  The  plant 
cost  approximately  $2,000,  and  was  operated  by  a  gang  of  about  twenty  men,  in 
addition  to  the  carpenters  and  steel  men. 

MATERIALS  AND  COST. 

The  bid  for  the  concrete  work  was  $27,000,  and  for  the  completed  structure 
about  $64,000.  Some  2,050  cubic  yards  of  reinforced  concrete  were  laid  in  the 
building,  besides  1,900  cubic  yards  of  plain  concrete  in  the  foundations  and  founda- 
tion walls. 

Six  months  were  occupied  in  the  erection,  the  average  progress  above  the  base- 
ment being  about  fourteen  days  per  story.  The  quantity  of  steel  used  was  115 
tons,  and  its  cost  made  into  trusses  and  delivered  at  the  building  was  approxi- 
mately 3  cents  per  pound.  The  placing  was  said  to  cost  only  $1.50  per  ton. 

The  concrete  was  mixed  in  proportions  of  one  part  Atlas  Portland  cement,  two 
parts  sand  and  four  parts  stone,  the  labor  of  mixing  and  placing,  exclusive  of  the 
forms  and  steel  work,  being  about  $1.50  per  cubic  yard. 


167 


CHAPTER  XIII. 


BLACKSMITH  AND  BOILER  SHOP  OF  THE  ATLAS  PORTLAND 
CEMENT  COMPANY. 

At  the  plant  of  the  Atlas  Portland  Cement  Company,  in  Northampton,  Pa., 
concrete  is  used  extensively  in  construction,  not  only  in  foundations  and  for  the 
cement  storehouses,  but  also  for  the  floors  and  walls  of  the  newer  buildings. 

In  1906  a  new  blacksmith  and  boiler  shop  was  built  with  a  lo-ton  crane  ex- 
tending from  wall  to  wall  and  running  upon  reinforced  concrete  arched  beams. 
The  building  was  designed  by  the  company's  engineer  and  built  by  day  labor. 
It  is  shown  complete  on  the  opposite  page. 

DESIGN. 

The  shop  is  309  feet  9  inches  long,  55  feet  6  inches  wide  and  31  feet  2  inches 
high  to  the  bottom  of  the  roof  trusses,  this  height  being  necessary  for  the  traveling 
of  the  crane. 

The  plan  of  the  shop  is  shown  in  Fig.  92,  and  the  elevations  and  sections  in 
Figs.  93,  94,  95. 

The  walls  consist  of  piers  14  feet  on  centers,  with  wall  panels  and  windows  be- 
tween them.  These  piers  are  made  of  heavy  section  (see  Fig.  93)  to  support  the 
crane,  and  for  this  purpose  they  project  into  the  building  23  inches  as  far  up  as 
the  crane  runway,  and  at  the  top  are  connected  with  arches  which  are  laid  at  the 
same  time  and  form  a  part  of  the  wall.  The  arches  are  reinforced  with  five  34-inch 
rods  spaced  5  inches  apart.  The  crane  run  is  shown  in  section  BB,  Fig.  93,  and 
also  on  a  large  scale  in  the  detail  above  it.  An  8-inch  by  lo-inch  yellow  pine 
timber  is  bolted  directly  to  the  concrete  beam,  and  upon  this  rests  the  track. 
The  walls  between  the  piers,  which  are  dovetailed  into  them,  as  shown,  are  9 
inches  thick.  This  is  somewhat  excessive,  but  the  extra  quantity  of  concrete  may 
be  justified  by  the  low  cost  of  materials  and  the  lean  proportions  of  the  concrete, 
which  are  I  part  cement  to  4  parts  sand  to  5  parts  gravel.  There  is  no  reinforce- 
ment in,  the  wall  panels  except  directly  above  the  windows. 

Fig-  95  (p-  173)  shows  a  cross-section  of  the  shop  with  its  steel  roof  trusses 
and  an  outline  of  the  crane. 

CONSTRUCTION. 

Somewhat  unusual  methods  of  construction  were  employed.  The  piers  were 
first  run  up  to  the  full  height  of  the  building,  as  illustrated  in  the  photograph, 

169 


171 


Fig.  96.*  Then  the  panel  forms  were  placed,  as  in  Fig.  97,  and  the  concrete 
poured  between  them. 

The  widow  frames  had  been  set  in  advance,  so  that  the  openings  were 
formed  in  each  wall  panel  as  it  was  poured.  The  only  tie  rods  which  were  in- 
serted to  connect  the  piers  and  the  wall  panels  were  at  the  corners  of  the  building, 
where  J^-inch  horizontal  rods  21/?.  feet  long  were  placed  every  3  feet  in  height. 
(See  Fig.  93-) 

Fig.  98  is  a  photograph  illustrating  the  side  walls  after  completion. 


Fig.  95.— Cross  Section  of  Blacksmith  and  Boiler  Shop  of  the  Atlas  Portland  Cement 
Company.      (See  p.   169.) 

Above  the  foundations  of  the  shop,  792  cubic  yards  of  concrete  were  required, 
with  only  5,570  pounds  of  steel.  In  the  foundation  460  cubic  yards  were  laid  in 
addition.  The  concrete  was  mixed  by  hand,  and  the  usual  gang  consisted  of  2 
foremen,  17  men  mixing,  4  men  hoisting,  4  men  placing,  and  6  carpenters.  The 
wages  for  the  laborers  ranged  from  $1.20  to  $1.50  per  day,  with  a  $2  rate  for  the 
carpenters.  The  total  cost  of  the  concrete  in  the  foundations  and  walls  was 

from  a  different  building  of  the  Atlas  plant,  but  the 


*  This  photograph  and  the  two  which  follow 
method  of  construction  is  the  same. 


173 


Fig.  96. — Wall  Piers  for  an   Atlas  Portland  Cement  Company   Building.      (See  p.   173.) 


Fig.  97. — Panel  Wall  Forms   for  an   Atlas   Portland  Cement  Company   Building.      (See  p.   173.) 

174 


175 


$29,328,  which  is  equivalent  to  only  $4.93  per  cubic  yard  of  concrete,  an  exception- 
ally low  price.  The  cheapness  of  labor  partially  accounts  for  the  low  cost.  Ordi- 
narily, in  building  construction  with  thinner  walls  and  higher  material  and  labor 
costs,  the  unit  price  per  cubic  yard  will  be  greatly  in  excess  of  this  figure. 

The  forms,  of  hemlock  lumber,  costing  $25  per  thousand,  were  dressed  only 
on  the  side  next  to  the  concrete.  About  19,000  feet  of  lumber  was  used  at  a  cost 
of  $485,  the  labor  on  forms  being  about  $5,500.  Although  the  forms  were  used 
ten  times,  the  Engineer  estimates  the  salvage  for  another  similar  job  to  be  about 
60  per  cent.,  as  the  lumber  was  but  slightly  injured. 

On  the  surface  of  the  ground  next  to  the  building,  a  concrete  gutter  is  laid 
to  carry  off  the  surface  water  and  the  roof  drainage.  A  detail  section  is  given 
in  Fig.  99. 


Fig.   99. — Drainage   Gutter.      (See  p.    176.) 


COAL  TRESTLE. 


The  coal  trestle,  which  is  shown  in  the  photograph,  Fig.  100,  is  supported 
upon  bents  of  reinforced  concrete  13  feet  apart,  resting  upon  heavy  concrete 
foundations.  The  piers  of  each  bent  are  20  inches  square  and  capped  by  a  rein- 
forced concrete  girder  with  an  arched  bottom  surface.  Supporting  the  track  are 
pairs  of  channel  irons  bolted  to  the  concrete  girders.  At  intervals  in  the  trestle, 
diagonal  tie  rods  with  turnbuckles  are  placed  in  two  adjacent  bays,  the  rods  ex- 
tending from  the  top  of  one  bent  to  the  bottom  of  the  next,  so  as  to  guard  against 
danger  from  longitudinal  expansion  and  contraction  of  the  stringers  as  well  as  any 
longitudinal  thrust  due  to  the  movement  of  the  trains. 


176 


177 


CHAPTER  XIV. 


DETAILS  OF  CONSTRUCTION. 

To  provide  better  adhesion  or  bond  between  the  steel  and  concrete  than  is 
given  by  round  or  square  rods,  many  types  of  deformed  bars  have  been  invented, 
and  those  most  commonly  used  in  the  United  States  are  illustrated  in  the  pages 
which  follow.  Views  are  also  shown  of  a  number  of  systems  of  assembling  the 
steel  or  arranging  the  reinforcement  for  application  to  special  conditions. 

In  addition  to  this  digest  of  systems  of  reinforcement,  a  number  of  photo- 
graphs are  presented  of  details  of  construction  most  commonly  met  with  in 
reinforced  concrete  buildings.  In  this  connection  are  shown  photographs  of  con- 
crete block  walls,  surface  finish  for  concrete  walls,  concrete  piles,  and  concrete 
tanks. 

SYSTEMS  OF  REINFORCEMENT. 

RANSOME  TWISTED  BARS.— One  of  the  oldest  types  of  reinforcing  steel 
is  the  square  twisted  bar  illustrated  in  Fig.  101,  invented  by  Mr.  E.  L.  Ransome, 
of  the  Ransome  &  Smith  Co.,  and  used  as  long  ago  as  1894. 


Fig.   101. — Ransome  Twisted   Bar.      (See  p.  161.) 


Twisted  bars  may  be  purchased  ready  to  use,  or  on  a  large  job  may  be  twisted 
on  the  work.  The  number  of  twists  per  linear  foot  depends  upon  the  diameter; 
thus,  for  }4-inch  bars  there  may  be  five  twists  per  foot  and  for  i-inch  bars  one 
twist  per  foot. 

In  computing  cross-section  area  of  steel  in  reinforced  concrete,  the  twisted 
bars  are  figured  as  square  bars  of  the  dimension  before  twisting.  Twisted  bars 
are  employed  in  the  Pacific  Coast  Borax  Refinery  and  the  Bullock  Electric  Com- 
pany shop,  described  in  Chapters  IV  and  VII. 

178 


THACHER  BAR. — The  Thacher  bar,  Fig.  102,  was  designed  and  patented  by 
Mr.  Edwin  Thacher,  of  the  Concrete  Steel  Engineering  Company.  Round  bars  are 
rerolled  to  the  shape  indicated.  Thacher  bars  are  used  in  parts  of  the  Textile 
building,  Chapter  XL 


Fig.   102.—' 


(See  p.   179.) 


JOHNSON     CORRUGATED     BAR.— The     corrugated,     or     Johnson     bar, 
Fig.    103,   is   the   invention   of   Mr.   A.   L.   Johnson,   of  the   Expanded    Metal   and 


Fig.  103. — Johnson  or  Corrugated  Bar.      (See  p.  179.) 

Corrugated  Bar  Company.  It  is  a  form  of  square  bar  with  alternate  elevations 
and  depressions  to  grip  the  concrete.  The  normal  size  and  net  sections  are  given 
in  the  following  table: 

AREAS    AND    WEIGHTS    OF   JOHNSON    BARS    (NEW    STYLE). 

Nominal  diameter,  inches.     Area,  square  inches.         Weight  per  linear  foot. 
%  0.06  0.24 

1-3  o.i  i  0.38 

1/2  0.25  0.85 

H  °-39  1-33 

y*  0.56  1.91 

7/s  0.77  2.60 

I  1. 00  3-40 

i%  1.56  5-3i 

The  Johnson  bar  is  used  in  the  Wholesale  Merchants'  Warehouse,  Nashville, 
Tenn.,  described  in  Chapter  VIII. 

UNIVERSAL  BAR.— A  type  of  bar  somewhat  similar  to  the  Johnson  bar 
is  shown  in  Fig.  104.  This  is  manufactured  by  the  Rogers  Shear  Company  and  the 
sale  controlled  by  the  Expanded  Metal  and  Corrugated  Bar  Company. 

DIAMOND  BAR.— The  Diamond  bar,  Fig.  105,  is  one  of  the  most  recent 
types  of  rolled  bar  and  the  invention  of  Mr.  William  Mueser,  of  the  Concrete 
Steel  Engineering  Company.  The  sizes  correspond  to  those  of  square  bars  as 
shown  in  the  following  table: 

179 


AREAS  AND    WEIGHTS    OF    DIAMOND    BARS. 

SIZE l/4   in.  J^in.        l/2  in.       ^  in.       54  in.  %  in.  i  in.  1%  in. 

Area  in  square  inches.  .0625  ,1406         .25          .39           .56  -76  LOO  1.56 

Weight   per   foot 213  478           .85         i-33         i-Qi  2.60  3.40  5.31 


Fig.   104. — Universal   Bar.      (See  p.   179.) 


Fig.  105. — Diamond  Bar.     (See  p.  179.) 

COLD  TWISTED  LUG  BAR.— A  modification  of  the  twisted  bar  is  the 
twisted  lug  bar,  Fig.  106,  made  by  the  General  Fireproofing  Company.  This  bar  is 
used  in  the  columns  of  the  Forbes  Building,  described  in  Chapter  XII. 


(Patented) 


Fig.   106. — Twisted  Lug  Bar.       (See  p.  180.) 


KAHN  TRUSSED  BAR.— The  Kahn  trussed  bar,  Fig.  107  (p.  183),  invented 
by  Mr.  Julius  Kahn,  of  the  Trussed  Concrete  Steel  Company,  is  rolled  with  flanges, 
which  are  bent  up,  as  shown  in  the  figure,  to  resist  the  shear  in  the  beam.  The 
Kahn  bar  is  employed  in  the  Packard  Building,  described  in  Chapter  X. 

CUP  BAR. — The  cup  bar,  another  product  of  the  Trussed  Concrete  Steel 
Company,  is  rolled  with  four  longitudinal  ribs  connected  at  frequent  intervals  by 
cross  ribs  so  as  to  form  cup  depressions  between  them  designed  to  grip  the  concrete. 

Areas  of  cross-section  of  cup  bars  are  made  to  correspond  to  square  bars  of 
the  same  nominal  size. 

180 


EXPANDED  METAL  MESHES. 


Designation 

§ 

If 

§   . 
11 

1 

ll 

& 

.0 

H 

£* 

u  (£ 

2  2 

"  1 

w'o'S 

ss 

1 

S 

Section  in  ; 
Per  Foot 

PH    g 

"3   CO 

CO 

j! 

s 

Number  of 
.  in  Bundle 
Leng 

%,  in. 

No.  18 

Standard 

.209 

•  74 

4  ft.  or   5  ft.  x  8  ft. 

5 

X  in. 

"     13 

" 

•225 

.80 

6  ft.  x  8  ft.  or  12  ft. 

5 

240 

\Yz   in. 

"       12 

" 

.207 

.70 

4  ft.  x  8  ft.  or  12  ft. 

5 

1  60 

2       in. 

"       12 

'< 

.166 

.56 

5  ft.  x  8  ft.  or  12  ft. 

5 

200 

3       in. 

"     16 

" 

.083 

.28 

6  ft.  x  8  ft.  or  1  2  ft. 

10 

480 

3       in- 

"       10 

Light 

.I48 

•50 

6  ft.  x  8  ft.  or  12  ft. 

5 

240 

3       in- 

"       10 

Standard 

.178 

.60 

6  ft.  x  8  ft.  or  12  ft. 

5 

240 

3       in. 

"       10 

Heavy 

.267 

.90 

4  ft.  x  8  ft.  or  12  ft. 

5 

1  60 

3       in. 

"       10 

Ex.   Heavy 

.356 

I    20 

6  ft.  x  8  ft.  or  12  ft. 

3 

144 

3       in. 

"      6 

Standard 

.  -400 

1.38 

5  ft.  x  8  ft.  or  12  ft. 

3 

120 

3       in. 

"       6 

Heavy 

.600 

2.07 

5  ft.  x  8  ft.  or  12  ft. 

3 

120 

4       in. 

"     16 

Old  Style 

•093 

.42 

4%  ft.  x  8  ft.  or  9  ft. 

6 

216 

6       in. 

"       4 

Standard 

•245 

.84 

5  ft.  x  8  ft.  or  12  ft. 

5 

200 

6       in. 

"      4 

Heavy 

.368 

1.26 

5  ft.  x  8  ft.  or  12  ft. 

3 

120 

LATHING. 


Designation 

Gage  U.  S. 
Standard 

Size    of 
Sheets 

Sheets  in 
a  Bundle 

Sq.   Yards 
in  a  Bundle 

Weight  Per 
Sq.  Yard 

A 

24 

IS  x  96 

9 

12 

4^  Ibs. 

B 

27 

18  x  96 

9 

12 

3         " 

Special  B 

27 

20^x96 

9 

13^ 

2^     " 

Diamond  No.  24 

24 

22^  X  96 

9 

15 

3 

Diamond  No.  26 

26 

24  x  96 

9 

16 

2%     " 

181 


182 


V 


Fig.  107. — Kahn  Trussed  Bar.      (Set  p.  180.) 

EXPANDED  METAL.— One  of  the  oldest  forms  of  sheet  reinforcement  is 
expanded  metal  invented  by  Mr.  John  T.  Golding. 

Sheet  steel  is  slit  in  a  special  machine  and  then  pulled  out  or  expanded  so  as 
to  form  a  diamond  mesh.  For  convenient  reference,  the  standard  sizes  and  gages 
as  adopted  by  the  Associated  Expanded  Metal  Companies  are  shown  in  the  illus- 
tration, Fig.  108  (p.  182),  and  are  tabulated  on  page  181. 

Expanded  metal  for  slab  reinforcement  is  employed  in  the  Lynn  storage  ware- 
house, Chapter  VI,  and  the  Forbes  cold  storage  warehouse,  Chapter  XII. 


Fig.    109.— Laying   Clinton    Welded    Wire   in    Decauville   Garage,    New   York.      (See  p.  183-) 

CLINTON  WELDED  WIRE.— Clinton  welded  wire  fabric,  made  by  the 
Clinton  Wire  Cloth  Company,  is  manufactured  in  different  sizes  of  mesh  and 
different  gages  of  wire.  As  commonly  made,  the  longitudinal  strands  are  of 
larger  diameter  and  closer  spacing  than  the  cross  strands,  the  latter  being  chiefly 
to  prevent  construction  cracks  in  the  concrete.  The  wires  are  electrically  welded 
at  every  intersection. 

183 


C/to  s s 


J-ONf, 


CROSS    *v 


Fig.  110.—  Lock  Woven  Fabric  of  Standard  Gage.      (See  p.  185.) 


184 


The  fabric  is  furnished  in  diameters  of  wire  ranging  from  i/io  inch  to  3/10 
inch,  and  with  spacing  between  the  strands  from  2  inches  up  to  20  inches. 

The  laying  of  the  fabric  in  the  Decauville  garage,  New  York,  is  illustrated 
in  Fig.  109  (p.  183). 

LOCK  WOVEN  WIRE.— Lock  woven  wire  is  made  by  W.  N.  Wight  & 
Co.  It  is  similar  to  the  welded  wire  fabric,  except  that  instead  of  electric  welding 
the  intersections  are  bound  together  by  winding  them  with  soft  wire.  The 
various  gages  and  sizes  of  mesh  are  illustrated  full  size  in  Fig.  no. 

RIB  METAL. — Rib  metal,  illustrated  in  Fig.  noa,  and  made  by  the  Trussed 
Concrete  Steel  Co.,  consists  of  straight  bars  for  main  tension  members  connected 
by  light  metal  ties  which  serve  as  spacers,  and  also  are  useful  for  cross  rein- 
forcement. 

The  strength  of  the  metal  varies  with  the  spacing  of  the  ribs  so  as  to  provide 
various  areas  of  cross-section  of  steel  per  foot  of  width,  as  shown  in  the  table. 

RIB    METAL    AREAS    AND    SECTIONS. 

Area  section  of  one  rib  =  0.9  square  inch. 


Size  No. 

Width  of 
Standard  Sheet 

Square  Feet  per  Lineal 
Foot  of 
Standard  Sheet 

Area  per  Foot 
of  Width 

2 

16  in. 

1-33 

•  54  sq-  in- 

3 

24     " 

2.00 

.36        « 

4 

32     " 

2.67 

.27        " 

5 

40     " 

3-33 

.216     " 

6 

48     " 

4.00 

.18        " 

7 

56     '< 

4.67 

.154     " 

8 

64     " 

'5-33 

•  135     " 

Standard  Lengths — 8,  10,  12,  14  and  16  feet. 

FERROINCLAVE.— Ferroinclave,  invented  by  Mr.  Alexander  E.  Brown,  of 
the  Brown  Hoisting  Machinery  Company,  is  sheet  metal  bent  as  in  Fig.  in,  and 
spread  over  or  plastered  with  mortar  to  form  a  sheet  ijHs  inches  thick.  An  illus- 
tration of  the  placing  of  ferroinclave  is  photographed  in  Fig.  112  (p.  187). 


TRUSS  METAL  LATH. — A  form  of  slit  metal  is  made  by  the  Truss  Metal 
Lath  Company,  with  the  strands  bent  to  receive  plaster,  as  shown  in  Fig.  113. 

Truss  lath  comes  in  sheets  ranging  from  24  to  30  inches  wide  and  68  to  112 
inches  long,  and  in  three  gages. 


Fig.   HOa. — Rib  Metal.      (See  p.  185.) 

TRUSSIT. — Trussit  is  formed  by  expanded  metal  or  herringbone  lath  bent 
to  V-shape  section,  as  shown  in  Fig.  114.  It  is  manufactured  by  the  General 
Fireproofing  Company. 


Waterproofing  felt 


part  portland  cement 
Concrete \  1  parts  sand 

(.Hair  as  required 

Fie.  111. — Section  of  Ferroinclave  Roof.      (See  p.  185.) 

HENNEBIQUE  SYSTEM.— One  of  the  pioneers  in  concrete  construction 
in  Europe  is  Mr.  Hennebique,  in  France,  and  the  system  which  still  bears  his 
name  is  shown  in  Fig.  115. 

COLUMBIAN  SYSTEM.— The  special  forms  of  Columbian  bars  and  methods 
of  placing  them  are  illustrated  in  Fig.  116  (p.  190). 

186 


CUMMINGS  SYSTEM.— A  number  of  reinforcement  details  have,  been  in- 
vented by  Mr.  Robert  A.  Cummings,  as  illustrated  in  Fig.  117  (p.  191). 

In  the  illustration  at  the  top  of  the  diagram  is  shown  the  Cummings  method 
of  forming  the  bent-up  bars  and  attaching  them  to  the  tension  bars.  In  general 
the  plan  is  to  provide  tension  bars  with  ends  specially  anchored,  while  securely 


Fig.  112. — Placing  of  Ferroinclave  Roof. 


attached  to  them  are  small  rods  horizontal  in  the  middle  of  the  beam  or  girder, 
but  bent  up,  as  indicated,  to  pass  across  the  top  of  the  beam  and  form  inclined 
inverted  U  bars  or  stirrups.  The  idea  is  more  clearly  shown  in  the  sketches  below 
of  "Arrangement  of  Steel."  The  "Supporting  Chairs,"  placed  at  the  point  of  the 


bending  up  of  the  rods,  are  also  drawn.  For  the  slab  steel  another  type  of  sup- 
porting chair  is  employed,  as  illustrated  in  the  detail  sketch. 

The  Cummings  hooped  column  is  also  shown  in  the  upper  sketch,  and  the 
details  of  the  column  reinforcement  below.  Each  hoop  is  securely  attached  to  the 
upright  rods. 

UNIT  GIRDER  FRAME  SYSTEM.— A  type  of  reinforcement  for  beams  and 
girders,  which  is  built  in  the  shop  or  in  the  yard  where  the  building  is  being 
constructed,  is  shown  in  Fig.  118  (p.  192).  This  is  the  unit  girder  frame,  manu- 
factured by  Tucker  &  Vinton. 

PIN-CONNECTED  SYSTEM. — A  modern  form  of  unit  reinforcement,  made 
by  the  General  Fireproofing  Company,  where  the  bars  are  made  into  a  truss 
before  placing  in  the  form,  is  shown  in  Fig.  119  (p.  193)- 


Patented 


Fig.   114. — Trussit.      (See  p.   186.) 


GABRIEL  SYSTEM.— Details  of  the  Gabriel  system,  as  laid  by  the  Gabriel 
Reinforcement  Company,  are  shown  in  Fig.  120  (p.  193). 

ROEBLING  SYSTEM.— The  Roebling  system  is  employed  in  connection  with 
a  structural  steel  frame  of  I-beam  or  girder  construction. 

For  all  flat  construction  of  floors,  the  reinforcing  system  used  consists  of 
flat  bars  placed  upon  edge,  secured  at  the  ends  to  the  steel  beams  and  bridged 
with  bar  separators.  The  object  of  the  edgewise  position  of  the  bars  is  the 

188 


increased  protection  thus  secured  to  the  reinforcing  steel.  With  this  type  of  floor 
the  structural  steel  frame  is  generally  completely  encased  with  concrete. 

For  light  roof  construction  where  the  steel  work  need  not  be  protected,  a 
continuous  slab  is  built  over  the  beams,  reinforced  with  flat  steel  bars,  3/16  by  i% 
inches,  placed  edgewise  and  held  in  position  by  spacers,  as  shown  in  Fig.  121  (p.  194). 

For  floor  construction  the  Roebling  Company  also  uses  segmental  arches  of 


Fig.  115. — Hennebique  System.     (See  p.  186.) 

cinder  concrete  laid  upon  permanent  stiffened  wire  lath  centering,  or  upon  wood 
centering  which  is  carried  on  steel  tees  and  supported  by  the  steel  I-beams  of  the 
floor  system,  which  are  generally  placed  about  7  feet  on  centers.  In  this  system 
the  material  is  placed  upon  the  centering  without  puddling  or  tamping,  in  order 
to  obtain  a  light  porus  concrete  of  high  fire  resisting  quality. 

MERRICK  SYSTEM.— To  lighten  the  weight  of  the  concrete  slab  Mr.  Ernest 
Merrick  has  designed  a  hollow  floor  construction,  as  illustrated  in  Fig.  122  (p.  194). 
Directly  upon  the  forms  a  2-inch  layer  of  concrete  is  placed,  and  before  this 
has  set,  oblong  boxes  of  metal  fabric  of  small  mesh  are  laid  horizontally,  with  the 
reinforcing  rods  in  the  spaces  between  them,  and  the  concrete  is  filled  in  between 
the  boxes  and  around  the  reinforcing  rods  and  covered  over  the  top  to  form  the 
floor. 


MUSHROOM  SYSTEM. — The  mushroom  system  of  flat  slab  construction  is 
the  invention  of  Mr.  C.  A.  P.  Turner.  The  rods  run  between  the  columns  both 
transversely  and  diagonally,  as  in  Fig.  123  (p.  195). 

The  interior  of  a  building  laid  by  this  system  and  showing  the  large  column 
capping  which  is  incident  to  it  is  illustrated  in  Fig.  124  (p.  196). 

FACTORY  MOLDED  CONCRETE. 

To  eliminate  the  cost  of  forms  and  at  the  same  time  to  utilize  to  best  ad- 
vantage the  strength  of  the  concrete,  the  plan  has  been  adopted  of  molding  in  a 


m 


Fig.    116. — Columbian   System.       (See  p.   186.) 

shop  the  various  members  for  a  concrete  house  or  factory,  and  transporting  them 
to  the  site  of  the  building  for  erection.  A  modification  of  this  plan  is  followed  in 
the  Textile  machine  shop,  described  in  Chapter  XI,  where  the  columns  were  built 
in  place,  but  the  girders  and  floor  beams  were  cast  separately  by  the  Visintini 
System  and  raised  to  place. 

Concrete  members  made  in  a  factory  are  subject  to  the  expense  of  transporta- 
tion to  the  site  of  the  building  and  to  the  erection  cost,  but  over  against  this  is  not 
only  the  saving  in  form  construction,  but  also  the  economy  of  manufacturing  the 
concrete  in  a  stationary  plant  where  machinery  can  be  utilized;  the  use  of  light 


sections  with  a  minimum  quantity  of  material;  and  the  advantage  of  an  initial 
seasoning  of  the  concrete  which  eliminates  danger  of  too  early  removal  of  forms 
by  inexperienced  contractors. 

In  the  larger  cities  where  a  plant  can  supply  the  local  demand,  this  type  of 
construction  is  an  economical  form  of  fireproof  construction,  especially  for  dwell- 
ings, apartment  houses  and  small  factories. 

A  building  of  separately-molded  members  lacks  the  extreme  rigidity  of  mono- 
lithic reinforced  concrete  construction  unless  the  connections  can  be  made  positively 
unyielding,  but  even  with  ordinary  care  it  should  be  possible  to  construct  at  least 
as  stiff  a  building  as  ordinary  mill  construction  with  its  brick  walls,  timber 
columns  and  beams,  and  plank  floors. 


Fig.   117.  —  Details  of  Cummings  System.     (See  p.  187.) 


In  Europe  the  Siegwart  system  of  floor  construction  has  been  developed  quite 
extensively,  using  for  floor  slabs  a  series  of  adjacent  hollow  beams  formed  by 
the  use  of  collapsible  cores. 

The  Standard  system  has  been  devised  and  is  now  being  manufactured  in  th 
United   States  by  the   Standard   Building  Construction   Co.,   of   Pittsburgh,    Penn. 
The  general  scheme  is  to  build  floors  of  light  weight  I-shaped  or  T-shaped  joists 
of  reinforced  concrete  to  replace  wood  joists  or  reinforced  concrete  slabs,  and  rest 
the  ends  of  the  joists   upon   walls  made  of  vertical   interlocking  concrete  studding 

191 


.    u 


192 


Fig.   119. — Pin-Connected  Girder  Frame.      (See  p.  188.) 

or  concrete  blocks.  Columns  are  formed  in  the  wall  in  light  construction  by  filling 
the  hollows  between  the  vertical  studs,  or  blocks,  with  concrete  reinforced  with 
steel  rods.  For  heavy  buildings  the  floor  joists  may  rest  upon  monolithic  rein- 
forced concrete  girders  and  columns,  or  upon  structural  steel  girders  and  columns 
fireproofed  in  the  factory  with  concrete. 

Fig.  1243  (p.  197),  illustrates  a  floor  joist  resting  upon  2-piece  hollow  block 
walls.  The  standard  joist  section  shown  is  16  inches  wide  by  81A  inches  deep,  with 
horizontal  reinforcement  for  tension,  and  webbing  of  metal  mesh  which  can  be 
seen  in  the  photograph,  to  provide  for  shear  and  the  stresses  which  are  liable  in 
transportation.  Members  of  other  dimensions  are  made  to  suit  the  span  and  loading 
required. 

A  nailing  piece  is  imbedded  in  the  top  of  the  joist,  as  shown,  for  laying 
wooden  floors.  If  the  floor  is  to  have  concrete  finish,  the  joists  are  made  I-shaped. 


GABRIEL    SYSTEM 

or 

REINFORCED  CONCRETE 


Pig.    120.— Gabriel  System.      (Stt  p.  188.) 
193 


The  ceilings  are  plastered   upon  the  lower  flanges,  the  concrete  being  left   rough 
for  the  purpose. 

Three  styles  of  Standard  floor  construction  are  illustrated  in  Fig.  12$*  (p.  198). 
The  top  floor  is  laid  with  joists  just  described,  the  two  middle  floors  of  separately 


Fig.  121. — Roebling  System.      (See  p.  188.) 

molded  arches,  and  the  bottom  floor  of  cast  slabs  with  reinforced  ribs  molded  on 
the  bottom  surface.     The  thin  slabs  are  also  well  adapted  for  roof  construction. 

An  important  feature  of  the  Standard  system  is  the  method  of  connecting  the 
individual  members.  The  reinforcement  is  allowed  to  project,  and  is  mechanically 
connected  after  placing.  The  connection  is  finally  imbedded  in  fresh  concrete  so 
as  to  give  strength  and  rigidity. 


1 


A: 


Fig.   122.— Merrick  Floor  System.      (See  p.  189.) 

CONCRETE  BLOCK  WALLS. 

Frequently  concrete  blocks  are  cheaper  for  factory  walls  than  solid  concrete, 
because  no  forms  are  required.  However,  if  used  in  combination  with  reinforced 
concrete  interior  construction  or  with  steel  beams,  they  must  be  securely  connected 
to  them  with  ties,  and  the  compressive  strength  of  the  blocks  carefully  figured  to 
see  that  there  is  sufficient  area  of  concrete  to  carry  the  weight. 

In  the  warehouse  at  Nashville,  Chapter  VIII,  concrete  blocks  are  utilized 
for  partitions. 

An  cxnmple  of  a  concrete  block  exterior  with  a  reinforced  concrete  interior 

194 


construction  is  shown  in  Fig.  125  (p.  199).  This  illustrates  the  Salem  Laundry 
Building,  Salem,  Mass.,  of  which  Ballinger  and  Perrot  were  architects,  and  Simp- 
son Brothers  Corporation,  builders.  This  has  a  reinforced  concrete  floor  system 
and  interior  columns  of  solid  concrete.  The  exterior  columns  are  hollow  blocks 
with  reinforcing  rods  running  through  the  openings  in  them  and  surrounded  by 
mortar  of  the  same  proportions  as  the  blocks  themselves  so  as  to  form  solid  piers. 

CONCRETE  METAL  WALLS. 

A  type  of  wall  in  which  the  molds  also  form  the  permanent  reinforcement  has 


Fig.  123. — Mushroom  System.     (See  p.  190.) 

been  designed  and  patent  applied  for  by  Mr.  S.  H.  Lea.  Two  walls  of  metal 
lathing  are  erected  and  plastered  and  the  concrete  poured  between  them,  as 
shown  in  Fig.  126  (p.  200). 

SURFACE  FINISH. 

One  of  the  most  perplexing  features  of  reinforced  concrete  construction  is  to 
obtain  a  pleasing  exterior  finish.  In  factory  construction  the  appearance  of  the 
building  is  usually  of  less  consequence  than  in  the  case  of  dwellings,  and  yet  the 
effect  must  not  be  distasteful  to  the  eye. 

Plastering  on  solid  concrete  or  on  concrete  blocks  is  unsatisfactory  in  climates 

195 


where  the  temperature  in  the  winter  months  falls  below  freezing.  A  very  thin  skin 
of  cement  may  be  plastered  on  by  a  skilled  mechanic,  but  this  is  apt  to  appear 
streaked  and  prove  unsatisfactory  over  a  large  surface.  If  the  surface  is  broken 
by  moldings  or  joints  this  plan  can  be  used  with  fair  results. 

An  excellent  finish,  although  a  somewhat  expensive  one,  is  obtained  by  re- 
moving the  surface  skin  of  cement  which  forms  against  the  molds  by  dressing  it 
with  a  pointed  hammer  of  a  pneumatic  tool.  This  method  is  illustrated  in  Fig.  127 
(p.  201),  and  a  photograph  of  the  same  wall,  taken  at  close  range,  is  shown  in 
Fig.  128  (p.  201). 

Another  style  of  finish  is  obtained  by  removing  the  wall  forms  within  twenty- 
four  hours  and  immediately  washing  the  surface.  To  do  this  satisfactorily  the 


Fig.   124.— Interior  of  Bovey  Building,  Built  by   the  Mushroom  System.      (See  p.   190.) 

concrete  cannot  be  laid  very  wet,  or  the  water  will  run  down  over  the  completed 
surface.     A  similar  effect  is  obtained  with  acid  treatment. 

Another  type  of  finish,  which  tests  of  several  years  in  New  England  has  shown 
to  be  satisfactory  if  properly  applied,  is  the  slap-dash,  illustrated  in  Fig.  129  (p. 
202),  which  is  a  view  of  the  wall  of  the  Lynn  storage  warehouse,  built  by  the 
Eastern  Expanded  Metal  Company,  and  described  in  Chapter  VI.  The  wall  is 
first  plastered  with  cement  mortar,  and  after  drying  the  slap-dash  is  thrown  on. 

196 


CONCRETE  PILE  FOUNDATIONS. 

In  certain  cases  concrete  piles  are  an  economical  substitute  for  wood  piles  or 
deep  pier  foundations.  Four  types  of  patented  reinforced  concrete  piles  are  illus- 
trated in  the  following  figures : 

The  Simplex  pile,  manufactured  by  the  Simplex  Concrete  Piling  Co.,  is  con- 
structed by  driving  a  hollow  shell  with  a  point  to  the  full  depth  and  gradually 
raising  the  shell  as  the  concrete  is  placed  in  the  hole  thus  made.  The  process, 
using  an  "alligator  point"  which  opens  when  the  shell  is  pulled,  is  shown  in  Fig. 
130  (p.  203).  Sometimes  a  solid  point  made  of  concrete  is  used,  which  is  left 
in  the  ground. 

The  Raymond   pile,  of  the   Raymond  Concrete   Pile  Co.,   is   formed  by  placing 


Fig.    124a.— Standard   Floor  Joists  resting  on   Concrete   Block   Walls. 


(See  p. 


concrete  in  a  thin  steel  tube.  The  tube  is  driven  with  a  collapsible  core  within  it, 
and  the  core  is  then  collapsed  and  withdrawn,  leaving  the  outer  shell  to  be  filled 
with  concrete.  The  driving  of  Raymond  piles  is  illustrated  in  Fig.  131  (p-  204). 

The  corrugated  pile,  patented  by  Frank  B.  Gilbreth,  Fig.  132  (p.  205),  is  cast 
on  the  ground  and  driven  by  a  pile-driver  with  the  aid  of  a  water  jet.     The  illus- 
tration shows  a  corrugated  pile  in  process  of  driving  for  the  foundation  oi 
warehouse  for  Mr.  John  Williams,  at  West  Twenty-seventh  street,  New  York  city. 

The  Gow  pile,  of  the  Chas.  R.  Gow  Co,  Fig.  133   (P-  206),  has  an  enlarged 
footing  so  as  to  give  it  larger  bearing,  and  is  formed  by  washing  down  a  tube  with 

197 


198 


Fig.    125.— Concrete     Block   Walls,   Salem   Laundry.         (See  p.   195.) 
199 


EXPLANATION. 


A  = 

B  = 

C  = 

D  = 

O  = 


Wire  Fabric. 

Spacing  Bar. 

Vertical  Member. 

Separator. 

Horizontal  Member. 


A  frame  of  the  desired  form  is 
erected  of  structural  rteel  and 
covered  with  wire  fabric  a  s 
shown.  A  coating  of  cement  or 
mortar  is  then  applied  to  the 
outside  of  the  wire  fabric  which, 
upon  hardening,  forms  a  shell  of 
the  desired  outline,  which  may 
be  filled  int  with  concrete.  This 
method  of  construction  does  not 
require  the  use  of  forms  or 
molds,  thus  effecting  a  great 
saving  in  material  and  labor, 
besides  affording  a  strong,  well- 
finished  structure.  If  may  be 
employed  in  ^  building  dams,  re- 
taining walls,  culverts  and  other 
structures. 


-1 


-g' 


SHwmimi! 


t. 


Fig.  126.— Lea's  Concrete  Metal  Wall  Construction. 


(See  p.    195-) 


Fig.   127.— Tooling  the  Surface  of  Friedenwald  Building  Walls.      (See  f.   196  ) 


Fig.   1 28.— Photograph  of  Tooled  Surface.      (See  p.   196.) 
201 


Fig.  129. — Photograph  of  Spatter  Dash  Finish  of  Lynn  Storage  Warehouse.       {See  f>.   196.) 

a  water  jet  to  a  firm  strata,  and  then  enlarging  the  bottom  of  the  excavation  by 
an  expanding  arrangement  to  form  the  base  of  the  pile.  The  apparatus  is  with- 
drawn and  the  space  filled  with  concrete. 

DRIVEN  PILES. — In  many  cases  where  too  many  boulders  are  not  liable 
to  be  encountered,  piles  of  rectangular  or  round  shape  are  built  horizontally  upon 
the  ground,  reinforced  with  steel  rods,  and,  after  setting  for  at  least  a  month,  are 
driven  with  a  pile  driver.  A  special  form  of  cap  is  required  to  break  the  force  of 
the  ram  on  the  head  of  the  pile.  The  corrugated  pile  (Fig.  132)  is  a  special  type 
of  driven  pile. 

TANKS. 

Reinforced  concrete  is  being  used  to  a  large  extent  for  tanks  to  contain 
fiquids.  They  require  careful  design  to  see  that  there  is  sufficient  steel  to  resist  the 
pressure,  and  also  very  careful  proportioning  and  placing  of  the  concrete. 

A  system  of  square  tanks  or  vats  in  the  basement  of  the  American  Oak  Leather 
Company,  Cincinnati,  is  illustrated  in  Fig.  134.  These  are  6  feet  by  8  feet  and  6 
feet  deep,  with  reinforced  walls  4  inches  thick.  They  were  built  in  groups  of  six 
by  the  Ferro-Concrete  Construction  Company  with  specially  prepared  aggregates. 
These  vats,  after  over  a  year's  service,  have  given  entire  satisfaction  and  show  no 
signs  of  leakage. 

202 


r 


Fig.  132.— Gilbreth  Corrugated  Pile.      (See  f.  197-) 
205 


o    (  o 


Fig.   133.— Cow  Pile.       (See  p.   197.) 


206 


207 


MISCELLANEOUS  BUILDINGS. 


£?* 


210 


211 


212 


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213 


214 


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215 


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216 


217 


218 


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220 


221 


222 


224 


MANUFACTURERS'   FURNITURE   EXCHANGE   BUILDING,   CHICAGO,   ILL. 
sn.sions  70  ft.  by  170  ft.     Wm.  Ernest  Walker,  Architect;  Mortimer  &  Tapper,  Builders; 
Condron   &  Sinks,   Consulting  Engineers. 


225 


SELBY    LEAD    SMELTING    PLANT,    SELBY,    CALIFORNIA. 
Lindgren-Hicks  Co.,  Builders;  John  B.  Leonard,  Consulting  Engineer. 


COLGATE  SOAP   FACTORY,   JERSEY  CITY,   N.  J. 

Dimensions  85  ft.  by  104  ft.     William  P.  Field,  Chief  Engineer; 

The    Concrete-Steel    Co.,    Builders. 


SOAP   WAREHOUSE   OF   KIRKMAN   <&  SON,   BROOKLYN,   N.   Y. 
Expanded   Metal   Engineering   Co.,    Engineers. 

227 


228 


\ 


229 


232 


233 


234 


JOHNSON'S  SQUARE  A*0  UNIVERSAL  FLAT  SECTIONS 
r«M««u«»w«  FOR  REINFORCED  CONCRETE.  "^"i,^" 

MANUFACTURED    UNDER  UCENSCO  PATENTS.  MAI'N   'III 

EXPANDED  METAX  &  CORRUGATED  BAR  Co. 

C.BLE.ODRESS:  CORR..«.  ST.  LO U I  S,MO..U.SA.  August   28*.    1907. 

\ddress  all  Communications  to  Company. 


Atlas  Portland  Cement  Ce., 
New  York.  N.  T. 
G«ntl«m»n:-- 

We  have  used  lare»  queuitltles  of  Atlas  Portland  cement  as 

purchased  through  your  several  agencies,   and  have  always  obtained  satisfactory 
and  Uniterm  results  from  its  us*  in  our  reinforced  concrete  work. 

Tours  very  truly, 
EXPANDED  METAL  AND  CORRUG/tTED  BAR  COMPAHT. 


VICE-PRESIDKNf 


233 


&  i^mttlj  OIn. 

Managing  (Eonmt*  lEnginma 


The  Atlas  Portland  Cement  Co., 
30  Broad  St.. 

Hew  York  City. 
Gentlemen :- 

Answering  your  inquiry  of  Aug.  26th..  in  re- 
gard to  your  cement,  we  take  pleasure  in  advising  you 
that  we  have  used  a  considerable  quantity  with  satis- 
factory results. 

Yours  truly. 

RAJ! SOME  fc 

Per 


tie  RaneOBS  *  Smith  Co., 

11  Broadway, 

New  Tork  City. 

Gentlemen: 

Answering  your  query  as  to  whether  the  factory  building  you  erected  for  ue  at 
Bayonne,  N.  J,,  about  10  years  ago,  has  been  satisfactory;  and  also  what  its  special  advant- 
ages -  if  any  -  are:       I  beg  to  say  the  building  has  been  satisfactory  in  every  '«•;•• 

As  you  know,  since  you  erected  the  firet  building  for  us,  we  have  had  you  erect 
additional  buildings  that  in  the  aggregate  are  considerably  larger  than  the  flret  building 
you  constructed.      we  would  not  for  a  moment  ccnelder  putting  up  any  building  other  than 
•  concrete  building  of  your  construction. 

Among  some  of  the  special  features  that  occur  to  me,   are  - 

71-st:       Its  being  absolutely  fire-proof.      This  was  fully  tested  &e  you  well  know 
by  the  fire  *lch  we  bed  in  our  Calcining  Department.      The  feed  pipe  conveying  the  fuel  oil 
to  the  burner,  broke  Just  back  of  the  burner  -  flooding  the  floor  with  burning  oil  -  making 
a  fire  of  terrific  heat  -  meltinr  all  exposed  metal  and  burning  all  combuetible  partitions, 
etc.  that  the  building  at  that  tile  contained:    but  the  concrete  building  itself  stood  vie 
test  magnificently,  and  as  our  property  is  surrounded  by  stills  of  the  Standard  Oil  Co.. 

ly  fire-proof. 

Second:      Cost  of  Repairs.      No  expenditure  under  this  heading  is  made  :  the  building 
being  monolithic  and  like  Spanish  wine,  improves  with  age. 

Third:       Strength.       Ae  you  know  we  carry  terrifl»  loade  on  our  floors  •  on  our 
fourth  floor  parrying  a  wetgit  of  1430  Ibs.  per  sq.  ft.      On  the  lower  floors  we  have  car- 
ried mu*  heavier  weights  without  straining  the  building  in  the  least. 

Tourth:      Cleanliness.      Your  conetruction  is  an  ideal  construction  for  a  factory  as 
it  can 'be  kept  perfectly  clean  -  it  being  a  elmple  matter  to  hose  and  wash   it  out. 

We  believe  that  ccr.crete  construction  is  the  proper  construction  and  that  fee 
Ransome  system  is  the  Vest  system.       Our  factory  buildings  ar*  certainly  a  r'nvir.clng 
dsmonstratlon  of  -mat  can  be  done  with  concrete  with  your  system,  and  they  have  more  than 
fulfilled  every  guarantee  ytu  gave. 

You-s  very  truly. 

Pacific  I 
C.B.Z.-RS 


237 


BALLINGER.  INDUSTRIAL     PUNTS 

AUOCAM.INST  orAnCHFTECTS  V  INSTITUTIONAL     BUILDINGS 


EMIUE    C.  PERROT. 


FORCED  CONCRETE   SPEC1A 


8ALLINGER    ft    PERROT 

ARCHITECTS  AND  ENGINEERS 

ISOO  CHESTNUT  STREET 

PHILADELPHIA 


*ug.   27,    1907. 

Atlas  Portland  Cement  Company, 

30  Bread  St.,  New  York.  N.  Y. 
Gentlemen :- 

Irt  reply  to  your  favor  of  the  24th    inat.,   asking  us  t»  write  you 
stating  ^.at  success  we  have  had  with   Atlas  Portland  Cerwnt,   would  say  that  taia 
cement  has  been  used  in  considerable  of  our  work,   the  most  netable  instance  being 
that  of  Hit  ei^it-story  Ketterliraus  Printing  House  at  Fourth  and  Arch   Street, 
Hiiladelthia.   erected  two  years  ago.       This  building  was  the  first  high   reinforced 
concrete  building  ejected  \n  Pn iladeljhia.       There  were  all  sorts  of  projhecies 
of  disaster  made  to  the  owners  and  ourselves  in  connection  with    it.       We  are  glad 
to  say  that  th A se  proved  to  be  false  prophecies,   and  that  the  building  is,   in 
every  way,   successful,   is  very  heavily  loaded  with   paper  and  heavy  printing  and 
li*ogr>ijhing  presees. 

Every  carlead  of  cement  used  was  tested  according  to  our  standard 
specifications,   and  met  the  tests  all  right. 
Yours  truly, 

WFB/K 


March  6,   1907. 


Die  Atlas  Portland  Cenent  Co., 

30  Broad  Street,  He*  York,  N.  T. 


Answering  your  letter  of  February  28th,  asking  *ether  our  eight  story 
reinforced  concrete  building,   in  *ich  your  cement  was  used,  is  satisfactory  or 
not,   I  am  pleased  to  state  that  it  is  all  that  I  could  expect  and  fully  up  to 
*at  Messrs.  Ballinger  *  Perrot,   Architects  and  Sngineers,  predicted  that  it 
would  be. 

The  concrete  portion,  erected  la  190S,  is  in  every  way  superior  to  the 
portion  erected  in  1893,  ihich  was  of  steel  frame  fireprocfed  with  terra  cotta. 

The  reinforced  concrete  portion  of  the  same  size  cost  much  less  than 
the  other,  though  the  cost  of  building  construction  was  much  greater  during  the 
latter  than  the  former  period. 

Our  opportunities  for  comparing  the  two  ccnstructions  are  ideal,   and  we 
subject  both-  portion*  to  equally  severe  usage,  having  large  printing  and  lithograph- 
ing presses,  wiping  from  12  to  20  tons  on  the  third,   fourth  and  fifth   floors  of 
each  portion,   and  both  parts  being  abcut  equally  levied  with  heavy  papej  and  other 
material. 

We  believe  our  insurance  rates  are  lower  than  any  building  in  this 
section  of  the  city. 

Tours  tr-ily, 


EASTERN  EXPANDED  METAL  CO., 

MANUFACTURERS  OF  EXPANDED    METAL 

AND    CONTRACTORS    FOR 

.  .  REINFORCED   CONCRETE  .  . 

PADDOCK   BUILDING. 

101    TREMONT  »TRCCT. 

BOSTON,         Sept.   3rd.   1907. 


Atlas  Portland  Cement  Co., 

30  Broad  St.,  New  York  City. 
Dear  Sirs.— 

In  reply  to  your  favor  «f  the  3rd  inst.,  beg  to  say  tiiat  we  have 
used  and  are  using  Atlas  Portland  cement  on  some  of  our  most  important  work  and 
have  found  it  uniformly  reliable  and  always  up  to  our  expectation.      He  feel 
that  *en  we  use  Atlas  in  eur  work  we  have  no  reason  to  'fear  any  results  but 
the  best. 

Tours  truly, 

EASTERN  EXPANDED  METAL  CO. 


T/H  General  Manager. 


LYNN  STORAGE 
WAREHOUSE  CO. 

152-158  PLEASANT  ST.. 


I,   23,    1907. 


Atla*  Portland  Cement  Co., 
30  Broad  Street. 

New  York,    N.   Ytt 
Gentlemen :- 

Rai.-lyi.ig  to  your  request,   we  wculd  say,    that  the  Eastern  Expanded  Metal 
Co..    cf  Boston,   constructed  for  us  a  nix  story  building  for  general  storage 
purposes,   entirely  of  reinforced  concrete,   using  Atlas  Cenent  in  the  construct- 
ion,  and  we  are  ve^-  nuch  pleased  with  the  butld*'ng. 

We  find  the  structure  to  be  ve^y  firm  and  rigid  and  tfiile  the  cost  »as 
slightly  greater  than  a  building  of  mill  construction  would  have  been,  thia..ia- 
amply  covered  by  the  fact  that  we  have  a  permanent  structure  absolutely  fire- 
proof,  and  a  lower  rate  of  insurance  for  ourselves  and  ou--  patrons;  besides  secur- 
ing a  large  amount  cf  businasa  tfiich   we  could  not  get  in  a  non-fireproof  building. 

Also,   we  note  that   this  construct!- n  gives  us  much    thinner  walls  than 
wculd  have  been  necessa-y  with  mill  construction,   ih.ich  increases  our  floor  area 
about  7  per  cent,   and  thus  adds  this  amount  te  our  earning  capacity. 

The  construction  is  so  permanent  and  stable  that  the  "Depreciation  of 
Plant"  account  'is  practically  nothing. 

Youra  very  truly, 

Lynn  Storage  Warehouse  Co., 


Diet.   W/W 


(7 


THE  FERRO  CONCRETE  CONSTRUCTION  Co. 

CINCINNATI 


August   26,    1907. 

The  Itoores-Coney   Supply  C«., 

Cincinnati.   Uiio. 
Gentlemen  :  - 

V*  have  been  using  Atlas  Portland  Cement,  on  and  off,   for  fte  last 

five  years.       During  this  tune  we  have  tested  every  car  and  »e  have  never  reject- 

• 
eU  a  car;   the  cement  has  been  entirely  satisfactory  in  every,  respect. 

Yours  very  truly, 

THE  FERRC  CWOBtf:  CONSTRUCTION  CO. 


TF/CB  SeVy. 


*  Treas. 


242 


Addrest  all  communications  to  the  Company. 

THE  BULLOCK  ELECTRIC -MANUFACTURING  Co. 

OF  CINCINNATI,  U.  S.  A. 

DIRECT  AND  ALTERNATING  CURRENT  MACHINERY. 

CINCINNATI,  u.s.  A.  May  17th,   1907. 


Ferro  Concrete  Construction  Co.. 

City. 
Gentlemen: 

Replying  to  your  letter  of  May  11*.,   in  reference  to  the  extension 
to  our  3iop  No.   3  built  by  your  Company,  would  sa;;  that  we  have  been  manufactur- 
ing in  this  building  for  the  past  year  and  one-half. 

Die  lower  floor  is  used  as  a  medium  machine  shop,   and  is  furnished 
with   two  10  ton  cranes  in  either  bay.       'Ihese  cranes  are  in  continual  operation 
and   so  far  the  concrete  column  and  brackets  carrying  the  crane  girders  have 
showed  no  signs  cf  weakening,  having  st'-od  the  continual  jar  of  the  crane  in 
a  most  satisfactory  manner. 

The  second  floor  of  this  shop  is  used  as  a  li$it  machine  shop,   and  our 
floor  loada  are  excessive,   and  there  is'a  considerable  amount  of  high   speed 
machinery  in  operation  on  the  floor.       There  is  absolutely  no  vibration  and  the 
floor  has  shown  no  signs  of  cracks.       In  some  portions  the  load  is  at  least 
50^  greater  1han  figured  on. 

One  of  our  principle  reasons  for  deciding  on  a  Ferroconcrete  building 
was  tiiat  at  the  time  cf  the  erection  of  this  building  you  were  willing  to 
guarantee,   undor  bonus  and  penalty,   V  have  the  building- erected  in  90  days  less 
tine  than  we  could  get  deliveries  started  on  the  necessary  steel  for  girders, 
columns,    etc.    in  a  brick  steel  construction. 

Yours  very  truly. 

The  Bullock  Electric  Mfg.  Co. 


Supe  rintenaent . 
243 


if?  C03«TI«ACXOR» 

REIXJKOltCK!!)  CONCRETE 


II  BROADWAY. 

Aug.   38/07. 


Atlas  Portland  Cement  Co., 

#30  Broad  St.. 

New  York  City. 
Gentlemen : - 

We  have  us»d   large  quantities  of   Atlas  Portland  C«ment  in  sucti    reinforc- 
ed concrete  buildings  as  the  J.  B.  King  &  Company  Buildings.   Staten  Island;  the 
Keuffal  t  Esser  Buildings,  Hoboien,   N.  J.,   and  the  Bu*  Tenninal  Company  Buildings, 
Brooklyn,   and  the  excellent  condition  of  this  work  to-day  is  ample  demonstration 
of  the  merits  of  your  cement  f  or  higi-grade  work. 

Very  truly  yours. 


BUSH  TERMINAL  COMPANY. 

QFFICEOFTHE  PRESIDENT 

IOO    BROAD    STREET. 


NEW  YORK.  May  29,  1907. 

Atlas  Portland  Cement  Co., 

30  Broad  St.,  N.Y.Clty. 
Gentlemen :- 

Your  letter  of  April  24th,  asking  for  an  expression  from  us  as 
to  our  views  on  concrete  construction  for  factory  buildings,  was  duly 
referred  to  me,  but  in  some  way  mislaid,  and  has  just  come  to  hand. 

We  were  chiefly  influenced  to  adopt  reinforced  concrete  construc- 
tion for  our  Model  Loft  and  Factory  Buildings,  because  of  our  opinion  that, 
at  the  present  relative  prices  of  cement  and  steel,  concrete  buildings 
represented  the  most  economical  form  of  fire-proof  construction,  and  of  the 
additional  advantage  for  buildings, -where  the  operation  of  machines  of  var- 
ious types  'was  employed  upon  different  floors,  the  concrete  buildings, 
being  practically  of  monolithic  construction,  were  free  from  vibration 
which  is  an  objectiobale  feature  in  the  ordinary  steel  fire-proof  building, 
used  for  similar  purposes.  The  effect  upon  our  insurance  has  been  impor- 
tant, but  this  has  been  due  to  the  fire-proof  character  of  the  buildings, rath- 
er than  to  any  particular  method  of  construction. 
Yours  very  truly, 


( 

President* 
ITB 


245 


Cftaorete  Steel  Ck>s. 


Detroit,Mtdu    Auguet  27§  1907. 


Atlas  Portland  Cement  Co., 
30  Broad  Street, 

New  York  City. 
Gentlemen:- 

It  gives  us  pleasure  to  be  able  te  endorse  Atlas  Portland  Cement  wilhout 
mental  reservation  or  evasion. 

Every  bit. of  cement  used  under  the  Kshn  System  As  subjected  to  rigid 
scientific  tests,   and  that  Atlas  Portland  Cement  has  been  used  in  several  hundred 
Kshn  System  strictures  is  p  roof  positive  of  its  excellent  qualities. 

Our  laboratory  records  are  as  geod  an  endorsement  as  any  customer  could 
desire. 

Tour*  very  truly, 

TRUSSED  CONCRETE  STEEL  COMPANY 


246 


fll  16,    1907. 

Atlae  Portland  Cement  Company, 
30  Broad  Sti*6et, 

New  York  City. 
Gentlemen:* 

In  answer  to  your  Inquiry  as  to  advantages  of  concrete 

construction,   am  pleased  to  state,  that  cur  original  factory  was  about  150,000  sq. 
ft.   of  brick  buildings  and  mill  construction  floor  space. 

»«n  we  cane  to  enlargements,  we  were  Impressed  by  Hie 

advantages  of  concrete  construction,   and  in  the  past  two  years  have  added  to  our 
factory  upwards  of  250,000  sq.  ft.   of  floor  space  of  the  Trussed  Concrete  Steel 
Company's  construction  and  have  now  improcess  upwards  of  100,000  sq.  ft.  more, 
so  you  will  B«e  our  belief  in  1he  concrete  construction  is  very  deeply  rooted. 
First,   in  my  judgment,  you  get  the  best  fire-proof  .  conditions.       Second,  you  avoid 
the  delay  of  waiting  for  steel  and  work  proceeds  immediately  and  expeditiously  and 
without  the  disturbance  of  riveting.       Third,   the  ft  op  light  conditions  are  much 
better  with   the  Kehn  system  'of  concrete  construction  -than  witii  brick  work,  because 
the  piers  are  smaller.       The  conditions  in  tills  respect  are  fully  as  good  as  steel 
construction. 

In  addition  to  our  upwards  of  ten  acres  of  factory  floor 

space  in  Detroit,  there  is  now  nearing  completion  our  new  retail  store  in  New 
York  City,  Corner  Broadway  and  61st  Street,  also  of  ttie  Kshn  reinforced  concrete 
construction,  the  same  as  we  use  here  and  also  built  by  the  Trussed  Concrete  Steol 
Company.      We  have  other  work  in  contemplation  in  which  we  shall,  of  course,  continue 
to  use  Hie  Kehn  system  of  reinforced  concrete  construction. 
Very  truly  yours, 
P 


642, 


MOTOR  CAR  CCMPJOJY. 


247 


CONCRETE-STEEL  ENGINEERING  COMPANY, 

SUCCESSORS    TO    MKLAN    ARCH    CONSTRUCTION    COMPANY 

CONSULTING    ENGINEERS. 


I  DUCTS, 


KINDS  OK 

KTK-8TEKL 
SSTRUCTION. 


FOUNDATIONS. 


HAWK.    ROW 

BUILDING, 
NEW    YORK. 


NEW    YOKK 


Aug.    28th    1907. 


The  Atlas  Portland  Cement  Company, 
Department  of  Publicity, 

30  Bread  Street, 

New  York  City. 
Gentleman :- 

Ysur  cement  has  been  used  in  large  quantities  in  our  ecncrete-steel 
arch  bridges,  built  in  different  sections  of  *e  country  and  has  always  given 
complete  satisfaction.  We  consider  it  a  first  class  cement  in  every  way. 

Very  truly  yours, 
CONCRETE- STEEL  ENGINEERING  COMPANY 


CORPORATEO  I8OO. 


FULL   FASHIONED    KNITTING   MACHINES  (COTTON  SYSTEM) 


Mar.  6,  1907. 


The  Atla.  Portland  Cement  Company, 

No.  30  Bread  Street, 

New  York  City,  N..  Y. 
Oentlemen:- 

We  are  pleased  to  advise  you  that  the  concrete-steel  factory  building, 
wUch  we  erected  about  two  years  ago,   of  the   'Vieintini    construction,  in  acco 
with  plans  prepared  by  the  Concrete-Steel  Engineering  Company  of  New  York  City, 
has  given  Us  very  good  satisfaction. 

The  writer  saw  an  eAibition  in  St.  Louis  in  1903,  *ich  had  been  arranged 
by  the  Concrete-Stee.1  Engineering  Company,   and  wiich  exhibited  the  principles  of 
the   'Vislntlni'  systeo.      We  were  then  contemplating  the  erection  of  a  factory 
building  for  li$it  manufacturing  purposes,   and  one  of  our  main  objects  was  to  put 
up  a  building  *ich  would  be  as  nearly  fire  proof  as  possible  at  moderate  cost,  and 
waich  would  carry  a  low  insurance  rate  without  the  installation  of  a  sprinkling 
system.       This  object  has  been  accomplished  by  the  building  wiich  we  erected.      we 
have  a  rate  of  twenty  cents  for  tie  building  and  .forty  cents  for  the  contents,  from  the 
stock  companies,  *ich  rate  is  considerably  less  than  half  of  *at  we  paid  heretofore 
on  our  other  buildings. 

The  building  was  jut  up  during  the  winter  of  1904,  and,  except  a  few 
days  of  extremely  bad  weather,  the  operations  wer»  continued  uninterrupted  even 
*en  the  thermometer  was  down  to  almost  zero.       We  had  all  the  work  done  by  day  work 
or  sub-contract,   and  we  are  satisfied  that  we  have  a  first  class  job  and  a  good 
investment.      The  building  presents  a  nice  appearance,  and  the  contrast  between  the 
red  brick  curtain  walls  of  the  panels  and  the  cement  columns  and  wall  beams  is 
particularly  pleasing. 

Very  truly  yours, 
NER)CJS  Textile  Machine  Works. 


249 


THE  GENERAL  FII^EPI^OOFING  Go. 


VO  U  NOSTOWM.OH10.. 

'OQjyNO  CO.  SYSTEM  OP  REINFORCED  CO  NCR  ETC. 


I4T60     LUB    »AH. 


YOUNSSTOWN.OHIO;     AU€>  ^ 


Atlaa  Portland  Cement  Co., 

30  Bread  St.,   . 

New  York  City. 
Gentlemen : - 

Aa  Atlas  Portland  Cement  was  used  in  the  construction  of  th«  Grunewald 
Hotel,   New  Orleans,    La.,   and  the  Carpenter  Siop  building  for  the  National  Cadi 
Register  Co.,   Dayton,   0.,    in  connection  wilh   reinforcing  steel  furnished  by  this 
company,  vre  believe  the  accompanying  phetegrajhs  may  be  of  interest  to  you.       The 
two  buildings  are  respectively  excellent  illustrations  of  leng  span  f irjproofing 
and  entire,  reinforced  concrete  construction. 

Our  observation  of  the  concrete  work  en  these  buildings  is  in  harmony 
with  ourhigi  opinion  of  Atlas  Cement  and  you  are  at  1  Ibe-ty  to  use  -these  photo- 
grarfcs  as  you  may  desire. 

Yeurs  truly, 

Th«  General  Fi  reproof  ir 
AAL.RN 


250 


BT«SBYRQ  STREET 


i/2/1907. 


The  Atlas  Portland  Cement  Co., 

New  York. 
Dear  Sirs:- 

Replying  tc  your  valued  favor  cf  recent  date,  we  beg  to  advise  that  we 
are  constructing  a  five  story  concrete  building.       We  thought  ever  the  matter  very 
seriously,    and  after  due  consideration,  decided  tc  build  concrete  on  account  of  its 
stability,   durability  and  its  sanitary  characteristics,    and  last,   but  not  least, 
we  believe  it  is  more  ecrncrcical  in  the  end  en  account  of  reductitn  in  insurance  rates. 
We  are  seriously  considering  carrying  no  insurance  whatever,   for  the  building,   as  far 
as  we  can  see,    is  fireprcef  to  the  extent  that  we  belr'eve  it  would  be  impossible  to  set 
it  afire,     and  we  dc  not  think  the  cost  ever  ten  tc  fifteen  percent  above  the  cost  cf 
mill  constructi<n,   ar.d  we  gc  fu«-ther  in  saying  -that  ve   recommend  everyone  vho  contem- 
plates the  erectlcn  of  a  building  for  warehouse  purposes  to  build  of  concrete. 

Yours  truly, 

W.S.FCP"ES  &  CO. 


Announcement 


For  the  benefit  of  those  who 
desire  to  make  lasting  im- 
provements about  the 

FARM, 

FACTORY    or 
HOME, 

and  as  a  guide  to  those  who 
contemplate  new  construc- 
tions, we  have  published  the 
following  books  : 


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